KR101976566B1 - Method for controlling of growth of self-assembled Au nanoparticles on GaN - Google Patents

Abstract

According to an aspect of the present invention, there is provided a method of controlling the growth of an Au nanostructure on GaN by depositing Au in a pulse-raising deposition chamber and spontaneously forming the same by a heat treatment process, The average height, the side diameter and the density are controlled by the deposition thickness of the Au, the heat treatment temperature of the heat treatment process and the heat treatment time, wherein the deposition thickness is controlled in the range of 1 nm to 100 nm, the heat treatment temperature is 200 To 850 < 0 > C, and the annealing time is controlled within a range of 30 to 900 seconds.

Description

[0001] The present invention relates to a method for controlling the growth of self-assembled gold nanoparticles on GaN,

The present invention relates to a method for controlling the growth of gold nanoparticles spontaneously formed on GaN.

III-nitride semiconductors are widely used in various high power and high frequency band applications such as field effect transistors, high electron mobility transistors and microwave devices and short wavelength light emitting diodes (LEDs) due to their wide band gaps. In recent years, metal nanoparticles such as Au nanoparticles included in III-nitride applications have been greatly increased in research interest as promising candidates for improving the luminous efficiency of conventional LEDs. For example, optical output power increases of more than 80% have been demonstrated with InGaN / GaN green LEDs using Au nanoparticles.

Using Au nanoparticle matrices fabricated with multiple quantum wells, the internal quantum efficiency can be greatly improved due to the coupling between the quantum wells and the surface plasmons.

Surface plasmons are induced by coherent oscillation of free electrons on the surface of metal nanostructures by resonance with incident electromagnetic waves, and the resonance is controlled by a closely related relationship with the composition, size and density of the metal nanostructures Can happen.

Au nanoclusters and nanoparticles are widely used in a variety of electronic, optoelectronic, and bio-medical fields due to their great potential. The size, density, and composition of gold nanoparticles play an important role in the performance of these devices.

Recently, gold nanoparticles have attracted major research attention due to their potential applications in solar cells, memory, sensors, and bio-medical devices due to localized surface plasmon resonance, increased absorption, enhanced fluorescence and scattering. The performance of the corresponding devices is strongly dependent on the size and density of gold nanoparticles.

For example, gold nanoparticles exhibit localized surface plasmon resonance properties that enhance the absorption of light, thus providing meaningful improvements in the efficiency of the solar cell. Relatively large gold nanoparticles can achieve higher power conversion efficiencies. On the other hand, small-sized gold nanoparticles with increased density have the potential to improve the turn-on voltage and on / off current ratio in nanofiber-based memory devices

In addition, arrays of large gold nanoparticles of spherical shape can be used in the manufacture of lasers for sensing applications. In addition, gold nanoparticles can be used to improve performance for DNA detection in biomedical devices because they can increase fluorescence intensity.

Gold nanoparticles may also be implemented in quantum-thermal therapy and cancer diagnosis due to enhanced radioactivity properties such as absorption and scattering by strong electromagnetic fields on the particle surface.

On the other hand, the performance and lifetime of a semiconductor device such as a laser diode and a light emitting diode are determined by various factors constituting the device. In particular, the performance and lifetime of the device are greatly affected by the base substrate on which the devices are stacked. Accordingly, various methods for manufacturing a high-quality semiconductor substrate have been proposed. Recently, interest in III-V compound semiconductor substrates has increased.

Here, a typical III-V compound semiconductor substrate is a gallium nitride substrate, and a gallium nitride substrate is suitably used for a semiconductor device together with a GaAs substrate, an InP substrate, and the like.

In addition, because of its wide bandgap, strong chemical bonding, high electrical breakdown voltage, high electronic mobility and high melting point, GaN is high in high power devices such as UV LEDs, photovoltaics, power amplifiers, transistors and opto-bandgap optoelectronic devices. Attracting attention.

In order to precisely manufacture nanowires for various applications, a method for systematically controlling the size, shape and density of gold nanoparticles on GaN is required.

Prior art in this field is disclosed in Korean Patent Registration No. 10-1287611.

Korean Registered Patent No. KR 1287611B1 (Manufacturing Method of Silicon Nanowire)

The present invention provides a growth control method for shape, size, and density of spontaneously-formed Au nanoparticles by controlling a deposition thickness and a heat treatment temperature in a growth process on a GaN substrate.

The object of the present invention is not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood from the following description.

According to an aspect of the present invention, there is provided a method of controlling the growth of an Au nanostructure on GaN by depositing Au in a pulse-raising deposition chamber and spontaneously forming the same by a heat treatment process, The average height, the side diameter and the density are controlled by the deposition thickness of the Au, the heat treatment temperature of the heat treatment process and the heat treatment time, wherein the deposition thickness is controlled in the range of 1 nm to 100 nm, the heat treatment temperature is 200 To 850 < 0 > C, and the annealing time is controlled within a range of 30 to 900 seconds.

In addition, the deposition thickness is set to 3 (± 5%) nm, the heat treatment temperature is set to 200 to 300 ° C, and the shape of the grown Au nanostructure is maintained at 450 (± 5% And a control unit for controlling the control unit.

In addition, the deposition thickness is set to 3 (± 5%) nm, the heat treatment temperature is set to 350 to 550 ° C., and the annealing time is maintained at 450 (± 5% The nanorods and the hexagonal nanostructures are mixed.

In addition, the deposition thickness is set to 3 (± 5%) nm, the heat treatment temperature is set to 650 to 800 ° C., the shape of the grown Au nanostructure is set to hexagonal And is controlled by a nanostructure.

The annealing temperature was increased from 350 DEG C to 650 DEG C to maintain the density of the grown Au nanostructure at 3 (5%) nm and the annealing time at 450 (5%) seconds, Is increased by 1.56 (± 5%) times.

In addition, when the heat treatment temperature is 650 ° C, the density of the grown Au nanostructure is 4.84 (± 5%) × 10 ⁹ cm ^-2 .

The annealing temperature was increased from 650 ° C to 750 ° C while the deposition thickness was set to 3 (± 5%) nm and the annealing time was maintained at 450 (± 5%) seconds. And the density is controlled to be reduced by 1.21 (± 5%) times.

In addition, when the heat treatment temperature is 750 ° C, the density of the grown Au nanostructure is 4.01 (± 5%) × 10 ⁹ cm ^-2 .

Also, the deposition thickness is increased from 1 (± 5%) nm to 2 (± 5%) nm, wherein the heat treatment temperature is maintained at 650 ° C. and the heat treatment time is maintained at 450 (± 5%) seconds -, the grown Au nanostructures are formed into a triangular shape, and the size and density are controlled to be controlled.

Further, the grown Au nanostructure is controlled to be formed in a polyhedral shape by keeping the deposition thickness to 10 nm, maintaining the heat treatment temperature at 650 ° C and the heat treatment time at 450 (± 5%) sec.

The deposition thickness is increased from 3 nm to 100 nm, wherein the annealing temperature is maintained at 650 ° C and the annealing time is maintained at 450 (± 5%) seconds, and the average height is 765.9 (± 5%) at 22.3 %) nm and the side diameter is increased from 127.1 (± 5%) nm to 2442.8 (± 5%) nm and the density is increased from 4.01 (± 5%) × 10 ⁹ to 4.56 10 < ^{6 &} gt ^; cm < ^{2 &} gt ;.

Further, the average radius of the nanostructure according to the heat treatment time is controlled by the following relationship.

는 초기 평균 반경이고,

는 고정된 온도 상수임here,

Is the initial average radius,

Is a fixed temperature constant

According to an embodiment of the present invention, the shape, size, and density of spontaneously-formed gold nanoparticles on GaN can be controlled effectively by controlling the deposition thickness and the heat treatment temperature of the growth process on the GaN substrate.

Figs. 1 to 11 show examples of the structure of Au nanoclusters fabricated at a temperature ranging from 200 DEG C to 850 DEG C at a heat treatment time of 450 seconds for a deposition thickness of 3 nm on GaN.
12 shows the average density change of the structure of the Au nanoclusters fabricated at the annealing time of 450 seconds at the respective temperatures of 350 to 850 DEG C for the deposition thickness of 3 nm fixed on the GaN.
FIG. 13 shows the average height and diameter variation of the Au nanoclusters fabricated at a heat treatment time of 450 seconds at each temperature of 350 to 850 DEG C for a deposition thickness of 3 nm fixed on GaN.
Fig. 14 shows a change pattern of Au nanostructure produced by spontaneous formation on c-plane GaN according to Au deposition thickness of 1 to 100 nm for 450 seconds at 750 캜.
15 shows the average density variation of Au nanostructures spontaneously formed on c-plane GaN according to the Au deposition thickness of 1 to 100 nm for 450 seconds at 750 ° C.
FIG. 16 shows the average height and diameter variation of Au nanostructures spontaneously formed on c-plane GaN according to Au deposition thickness of 1 to 100 nm for 450 seconds at 750 ° C.
Figs. 17 to 23 show examples of the structure of Au nanoclusters spontaneously formed at a heat treatment time of 450 seconds at a temperature of 750 DEG C for each deposition thickness of 3 to 100 nm on c-plane GaN.
FIG. 24 shows energy-dispersive X-ray spectroscopy (EDS) element characteristics of an Au nanocluster structure fabricated with a deposition thickness of 100 nm.
Figure 25 shows a map of spontaneously formed Au nanostructures on c -plane GaN depending on the heat treatment temperature and deposition thickness.
FIGS. 26 to 30 show Au nanostructures prepared by spontaneous formation at a heat treatment temperature of 750.degree. C. for a fixed deposition thickness of 20 nm in accordance with each heat treatment time (AD) of 30 to 900 seconds.
31 shows the average height, diameter, and average density variation of Au nanostructures spontaneously formed at a heat treatment temperature of 750 DEG C for a fixed deposition thickness of 20 nm and a heat treatment time (AD) of 250 to 900 seconds .

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, when a component is referred to as " comprising ", it means that it can include other components as well, without excluding other components unless specifically stated otherwise. Also, throughout the specification, the term " on " means to be located above or below the object portion, and does not necessarily mean that the object is located on the upper side with respect to the gravitational direction.

Hereinafter, a method for controlling growth of gold nanoparticles spontaneously formed on GaN according to an embodiment of the present invention will be described in detail.

According to an embodiment of the present invention, there is provided a method of manufacturing nanostructured and spontaneously-formed gold nanoparticles on GaN while varying the heat treatment temperature (Ta) and the deposition amount (DA).

The fabrication of Au nanostructures according to one embodiment of the present invention was performed on epi-ready semi-insulated GaN (0001) templates ~ 10 mu m thick.

Initially, the GaN sample is thermally degassed under vacuum at 1.0 x 10 < ^-4 > Torr for 30 minutes at 700 < 0 > C to remove contaminants.

Thereafter, Au deposition is performed in a sputter chamber with an ionization current of 3 mA, providing a growth rate of 0.05 nm / s under vacuum of 1 x 10 < ^-1 > Torr.

The fabrication process of spontaneously formed gold nanoparticles on GaN according to one embodiment of the present invention was performed in a pulsed laser deposition chamber and a programmed method was used to control the entire process.

The substrate temperature is controlled at a set temperature at a rate of 2 占 폚 / s under a vacuum of 1 占^10-4 Torr.

According to one embodiment of the present invention, in order to analyze the temperature control effect on the Au nanostructure, the temperature of the heat treatment is set to 200 < RTI ID = 0.0 >Lt; RTI ID = 0.0 > 850 C. < / RTI >

Further, at various Au deposition thicknesses of 1 to 100 nm, the growth process is performed at 750 캜 for 450 seconds to analyze the control characteristics according to the deposition thickness according to an embodiment of the present invention.

In order to analyze the control characteristics for the heat treatment time, a growth process is performed at 750 ° C. while controlling the change of the heat treatment time for 30 to 900 seconds at the deposition thickness of 20 nm of Au. In this case, a process of ramping up at a rate of 10 ° C / s is performed in order to minimize the growth error during heating. After each growth, the substrate temperature is immediately cooled to room temperature to prevent undesired Ostwald ripening.

An atomic force microscope (AFM) (XE-70, Parks Systems, Inc.) was used to analyze surface morphology characteristics according to one embodiment of the present invention, and the probe used was NSC16 / AIBS. The resonant frequency of the tip was ~ 270 kHz and the radius of curvature was less than 10 nm.

 XEI software was used to analyze 3D aspects, cross-sectional line-profiles, and Fourier transform transform power spectra from AFM data. For large surface morphology analysis, SEM (scanning electron microscope) (CX-200, COXEM, Korea) was used. An energy-dispersive X-ray spectroscope (EDS) (Noran System 7, Thermo Fisher, USA) was used for elemental characterization and spectral mapping. Raman and reflectance measurements were performed with an optical characteristic machine (UNIRAM II, UniNano Tech, Korea).

Figs. 1 to 11 show examples of the structure of Au nanoclusters fabricated at a temperature ranging from 200 DEG C to 850 DEG C at a heat treatment time of 450 seconds for a deposition thickness of 3 nm on GaN.

FIG. 1 shows an example of the structure of Au nanoclusters fabricated at a heat treatment time of 450 seconds at a temperature of 200 DEG C for a deposition thickness of 3 nm fixed on GaN.

1 (a) is an AFM plan view of a structure of Au nano clusters of 3 x 3 m ² , Fig. 1 (a-1) is an AFM plan view of 1 x 1 m ² , 1 (a-1) shows a cross-sectional line profile along the horizontal line shown in FIG. 1 (a-1), and FIG. 1 (a-3) shows a pre-filter transform (FFT) power spectrum of a sample of Au nanoclusters produced, 1 (a-4) shows an AFM side view of 1 x 1 탆 ² .

2 shows an example of the structure of an Au nanocluster fabricated at a heat treatment time of 450 seconds at a temperature of 250 DEG C for a deposition thickness of 3 nm fixed on GaN.

Fig. 2 (b) is an AFM plan view of the structure of the Au nanoclusters of 3 x 3 m ² , Fig. 2 (b-1) is an AFM plan view of 1 x 1 m ² , FIG. 2 (b-3) shows a pre-filter transform (FFT) power spectrum of a sample of Au nanoclusters produced, and FIG. 2 FIG. 2 (b-4) shows an AFM side view of 1 × 1 μm ² .

FIG. 3 shows an example of the structure of Au nanoclusters fabricated at a heat treatment time of 450 seconds at a temperature of 300 DEG C for a deposition thickness of 3 nm fixed on GaN.

3C is an AFM plan view of the structure of the Au nanoclusters of 3 x 3 mu m ² , Fig. 3C-1 is an AFM plan view of 1 x 1 mu m ² , and Fig. 3C- FIG. 3 (c-3) shows a pre-filter transform (FFT) power spectrum of a sample of Au nanoclusters manufactured, and FIG. FIG. 3 (c-4) shows an AFM side view of 1 × 1 μm ² .

Fig. 4 shows an example of the structure of Au nanoclusters fabricated at a heat treatment time of 450 seconds at a temperature of 350 DEG C for a deposition thickness of 3 nm fixed on GaN.

FIG. 4A is a side view of the AFM of 1 × 1 μm ² of the structure of the Au nanoclusters manufactured. FIG. 4A is an AFM plan view of 1 × 1 μm ² , 2 shows the cross-sectional line profile along the horizontal line shown in (a-1), and FIG. 4 (a-3) shows the AFM plan view of the 3 x 3 탆 ² structure of the fabricated Au nanocluster structure. And a pre-filter transform (FFT) power spectrum.

FIG. 5 shows an example of the structure of Au nanoclusters fabricated at a heat treatment time of 450 seconds at a temperature of 450 DEG C for a deposition thickness of 3 nm fixed on GaN.

Fig. 5 (b) shows the AFM side view of the 1 x 1 탆 ² structure of the Au nanoclusters produced, Fig. 5 (b-1) shows the AFM plan view of 1 x 1 탆 ² , 2 shows the cross-sectional line profile along the horizontal line shown in (b-1), and FIG. 5 (b-3) shows the AFM plan view of the 3 x 3 탆 ² structure of the Au nanocluster structure And a pre-filter transform (FFT) power spectrum.

FIG. 6 shows an example of the structure of Au nanoclusters fabricated at a heat treatment time of 450 seconds at a temperature of 550 DEG C for a deposition thickness of 3 nm fixed on GaN.

Fig. 6 (c) shows an AFM side view of the 1 x 1 占 퐉 ² structure of the Au nanocluster structure, Fig. 6 (c) shows the AFM plan view of 1 x 1 占 퐉 ² , 2 shows the cross-sectional line profile along the horizontal line shown in (c-1), and FIG. 6 (c-3) shows the AFM plan view of the 3 x 3 탆 ² structure of the Au nanocluster structure And a pre-filter transform (FFT) power spectrum.

FIG. 7 shows an example of the structure of Au nanoclusters fabricated at a heat treatment time of 450 seconds at a temperature of 650 DEG C for a deposition thickness of 3 nm fixed on GaN.

Fig. 7 (d) shows the AFM side view of the 1 x 1 占 퐉 ² structure of the Au nanoclusters manufactured, Fig. 7 (d-1) shows the AFM plan view of 1 x 1 占 퐉 ² , 2 shows the cross-sectional line profile along the horizontal line shown in (d-1), and FIG. 7 (d-3) shows the AFM plan view of the 3 x 3 탆 ² structure of the Au nanocluster structure And a pre-filter transform (FFT) power spectrum.

FIG. 8 shows an example of the structure of Au nanoclusters fabricated at a heat treatment time of 450 seconds at a temperature of 700 DEG C for a deposition thickness of 3 nm fixed on GaN.

Figure 8 (a) shows a modification showing an AFM plan view and a Fourier filter transform (FFT) power spectrum of a 3 × 3 ㎛ the structure of the prepared Au ^{nanoclusters. 2,} Fig. 8 (a-1) is 1 × 1 ㎛ ² 8 (a-2) shows an AFM plan view of 1 x 1 占 퐉 ² , and Fig. 8 (a-3) shows a sectional line - profile.

Fig. 9 shows an example of the structure of Au nanoclusters fabricated at a heat treatment time of 450 seconds at a temperature of 750 DEG C for a deposition thickness of 3 nm fixed on GaN.

Figure 9 (b) is a simplified showing an AFM plan view and a Fourier filter transform (FFT) power spectrum of a 3 × 3 ㎛ the structure of the prepared Au ^{nanoclusters. 2,} Fig. 9 (b-1) is a 1 × 1 ㎛ ² 9 (b-2) shows an AFM plan view of 1 x 1 占 퐉 ² , and Fig. 9 (b-3) - profile.

10 shows an example of the structure of an Au nanocluster fabricated at a heat treatment time of 450 seconds at a temperature of 800 DEG C for a deposition thickness of 3 nm fixed on GaN.

Figure 10 (c) shows a modification showing an AFM plan view and a Fourier filter transform (FFT) power spectrum of a 3 × 3 ㎛ the structure of the prepared Au nanoclusters. ^2, FIG. 10 (c-1) is a 1 × 1 ㎛ ² 10 (c-2) shows an AFM plan view of 1 × 1 ㎛ ² , and FIG. 10 (c-3) shows an AFM plan view of a section line - profile.

11 shows an example of the structure of Au nanoclusters spontaneously formed at a heat treatment time of 450 seconds at a temperature of 850 DEG C for a deposition thickness of 3 nm fixed on GaN.

Figure 11d) shows a modification showing an AFM plan view and a Fourier filter transform (FFT) power spectrum of the prepared Au nanostructures 3 × 3 ㎛ of the cluster ^2, and Fig. 11 (d-1) is 1 AFM side view of × 1 ㎛ ² 11 (d-2) shows an AFM plan view of 1 x 1 탆 ² , and Fig. 11 (d-3) shows an AFM plan view along the horizontal line shown in Fig. 11 FIG.

Referring to FIGS. 1 to 11, a change in the Au nanostructure due to the systematic control of the annealing temperature (annealing temperature) with 3 nm Au deposition for 450 seconds can be seen.

According to one embodiment of the present invention, the growth pattern of Au with a deposition thickness of 3 nm on GaN has four unique characteristics depending on the heat treatment temperature.

(i) At 200 to 300 DEG C, a nanostructure of the insect-like shape is formed.

(ii) Multilayer nanorods and hexagonal nanostructures are mixed at 350 to 550 ° C.

(iii) an Au hexagonal nanostructure is formed at 650 to 800 ° C.

(iv) Au hexagonal nanostructures collapsed at 850 ^{° C} are formed.

Referring to FIGS. 1 to 3, it can be seen that the Au nanoclusters and the nanocomposite nanoparticles formed in (i) are formed.

Aggregation of Au nanoclusters can be explained by solid state dewetting of the film caused by the high temperature heat treatment. Through heat energy from surface diffusion, metastable voids in the Au film can aggregate into the pores while the Au adsorbed atoms diffuse to aggregate into the nanostructures.

)와 밀접한 관계를 가질 수 있고, 다음 식에 의해 주어진다.Surface diffusion can play an important role in the nanostructure formation process. The surface diffusion coefficient ( D _s )

), And is given by the following equation.

(Equation 1)

는 각각 확산 장벽 상수 및 볼츠만 상수이다. here,

Are the diffusion barrier constant and the Boltzmann constant, respectively.

)는 다음과 같이

식으로 표현될 수 있다:Also, the diffusion length, which determines the average distance the adsorbed atoms can migrate on the surface

) Is as follows

Can be expressed as:

는 표면상의 흡착원자의 잔류시간이다. 상기 두 식에 따르면, l _D 는 열처리 온도와 직접적으로 관련이 있으므로 Au 흡착원자의 표면 확산은 열처리 온도가 증가할수록 증가할 수 있고 그 역도 가능하다.here,

Is the residence time of adsorbed atoms on the surface. According to the above two equations, 1 _D is directly related to the heat treatment temperature, so the surface diffusion of Au adsorbed atoms can be increased as the heat treatment temperature increases and vice versa.

The higher the diffusion, the greater the probability of the Au adsorption atoms moving further away, and the surface morphology can be changed accordingly. In addition, Au nanostructures can be grown to 3-D islands based on the Volmer-Weber growth model because the binding energy between Au atoms can be greater than the binding energy between Au and GaN atoms have. 1 (a) - (a-1), small dense pin-holes appear in the Au film due to nucleation of the pores at 200 ° C.

 When the heat treatment temperature was increased to 250 ° C, pores were grown and aggregation of small Au nanoclusters appeared as clearly shown in FIG. 2 (b-2).

At 300 占 폚, as shown in Figs. 3 (c) - (c-1), a relatively long surface diffusion length is shown in the formation of Au nanoclusters in the form of isolated insect pests.

Due to the increased surface diffusion, the pores grow and holes are created on the Au film.

The formation of the pores can cause the film to break because it induces a change in the surface, and can be agglomerated into the insect-like nanostructure due to Rayleigh instability. As a result, the change can be passed through the formation of new pores and nanostructures, and the formation of wavy Au nanostructures can be radially generated from the pore-generating sites according to a diffusion-limited cohesion model.

The line-profile also shows that the average height of the nanostructure increases as the annealing temperature increases.

As shown in Figs. 1 (a-2) to 3 (c-2), the height of Au nanostructures gradually increased from ~ 1.5 nm to ~ 4 nm at 200, 250 and 300 ° C, do.

As shown in Figs. 1 (a-3) to 3 (c-3), the height distribution and the surface roughness gradually increase by the FFT power spectrum.

1 (a-3) shows a circular spectral pattern with a tilted center, which can be induced by the atomic phase of GaN.

Referring to FIG. 2, the spectral pattern at 250 ° C gradually brightened with increasing height distribution, and a bright and circular pattern was finally observed in the FFT power spectrum due to the increase in nanostructure size.

At the same time, it can be seen that the circular pattern has no preference for orientation in the formation of the nanostructure.

Figs. 4 to 7 show Au nanostructures prepared in the above-described characteristic (ii).

Referring to FIGS. 4 to 7, the Au comb-shaped nanostructures have the feature of gradually growing into multi-faceted nanorods and hexagons.

Structural changes can be explained based on the continuously increasing surface diffusion associated with Au crystallization at relatively high annealing temperatures.

As the heat treatment temperature is further increased, the insect shape nanostructures break through increased surface diffusion.

 The breakage of the Au nanoclusters is analyzed to be that the Au nanoclusters may be broken due to the increased thermal energy and the inability to maintain the irregular shape.

Thereby breaking into relatively small nanostructures such as nanorods and hexagons with high surface energies that are more thermodynamically stable.

As the formation of the surface is observed with nanorods and hexagons, it is analyzed that the increase of annealing temperature is favorable for Au crystallization.

Due to the anisotropic distribution of surface energy in various directions, the formation of the surface can be a way to lower the surface energy of the crystal. Therefore, the multi-plane nanostructure is analyzed to be preferable to the hemispherical shape.

Referring to FIG. 4 (a), the wavy Au nanoclusters were separated at 350 ° C., and the height was slightly increased compared to 300 ^° C.

Referring to FIGS. 5 (b) -6 (c), at 450 and 550.degree. C., Au nanoclusters are clearly broken into irregular nanorods and hexagons.

When the heat treatment temperature was increased to 650 캜, the Au nanorods and the hexagonal shape were further broken, and the formation of the multi-faces was clearly observed as shown in Fig. 7 (d).

Referring to Figs. 4-7, such a structural change is evident in the FFT spectrum.

At 350 ° C, the spectrum shows a nearly circular shape with the formation of the insect-like nanostructure. When the heat treatment temperature was increased from 450 to 650 ° C, the spectrum pattern tended to evolve into hexagons such as multi-faceted nanorods and gradually form hexagons.

Referring to Figs. 8 to 9, in the above-described characteristic (iii), the overwhelming Au nanostructure is formed in a hexagonal configuration.

Referring to FIGS. 8 (a) -3 (a-1) and 9 (b) -9 (b-1) according to an embodiment of the present invention, Au is further crystallized at a heat treatment temperature of 700 to 750 ° C., The structure is formed in a hexagonal shape having a minimum surface energy.

Referring to Figures 10 (c-1) and 10 (c-2), when increased to a heat treatment temperature of 800 ° C, almost all nanoparticles appear as well-grown hexagonal shapes.

Finally, in feature (iv), the well-grown hexagonal shape collapses by heat treatment at 850 占 폚. Instead, referring to FIG. 11, it is analyzed that the rough surface shape and the hole are formed.

This distinctive form can appear due to the decomposition of GaN at high temperatures, whereby nitrogen can be desorbed in the form of N ₂ , and Ga can be adsorbed or alloyed with Au.

That is, at high heat treatment temperatures, the GaN substrate can be locally etched by Au nanoparticles, which can precipitate the nanoparticles after substrate decomposition.

At the same time, the nanoparticle size can be influenced by the increase in Au deposition at high annealing temperatures. Since the deposition rate can be promoted with increasing the heat treatment temperature, additional loss of Au mass can occur at a temperature higher than the same heat treatment time, thereby reducing the size of the nanostructures.

Thus, as mentioned above, the GaN substrate can be etched in the vertical direction of the nanoparticle site until the Au nanoparticles are completely deposited due to the decomposition of GaN at high temperature and the deposition of Au. Thus, a nano-hole can be formed together with the catalyst Au nanoparticles.

12 shows the average density change of the structure of the Au nanoclusters fabricated at the annealing time of 450 seconds at the respective temperatures of 350 to 850 DEG C for the deposition thickness of 3 nm fixed on the GaN.

FIG. 13 shows the average height and diameter variation of the Au nanoclusters fabricated at a heat treatment time of 450 seconds at each temperature of 350 to 850 DEG C for a deposition thickness of 3 nm fixed on GaN.

Table 1 shows the average densities, side diameters and densities of the structures of Au nanoclusters spontaneously formed at a heating time of 450 seconds at 350 to 850 ° C for a deposition thickness of 3 nm fixed on GaN (error range: ± 5%).

Temperature
[° C] Average height
[nm] Side diameter
[nm] density
[cm ^-2 ] 350 - - 3.09 x 10 ⁹ 450 - - 3.58 × 10 ⁹ 550 - - 3.64 x 10 ⁹ 650 18.8 91.3 4.84 × 10 ⁹ 700 20.9 109.6 4.30 × 10 ⁹ 750 22.4 127.0 4.01 × 10 ⁹ 800 15.2 125.9 4.00 × 10 ⁹

Referring to Figures 12, 13 and Table 1, as the temperature is increased from 350 to 650 ° C, the density of the nanostructures increases due to the continuous breakage of the Au nanostructures, resulting in a density of 3.09 (± 5%) × 10 ⁹ 4.84 (± 5%) × 10 9 cm - ² has a characteristic that increases 1.56 times.

However, due to increased surface diffusion at temperatures above 700 ° C, the adsorption between the nanoparticles causes a reduction of smaller nanoparticles resulting in a density of 4.84 (± 5%) × 109 at 650 ° C. and 4.01 (± 5%) at 750 ° C. 10 ⁹ cm ^{- 2} .

On the other hand, referring to FIG. 13 and Table 1, the average height of the Au hexagons increased from 18.8 (± 5%) to 22.4 (± 5%) nm by 1.34 times in the range of 650 to 750 ° C.

Further, the side diameter increased from 91.3 (± 5%) to 127 (± 5% nm, 1.39 times) in the range of 650 to 750 ° C.

On the other hand, the hexagonal height decreased to 15.2 (± 5%) nm and the side diameter decreased to 125.9 (± 5%) nm due to the rapid deposition of Au at 800 ℃.

According to the FFT power spectrum of FIGS. 8 to 11, the pattern has a hexagonal shape at 700 to 800 ° C. and has a pattern that is close to a circular shape after losing hexagonal shape at 850 ° C.

Fig. 14 shows a change pattern of Au nanostructure produced by spontaneous formation on c-plane GaN according to Au deposition thickness of 1 to 100 nm for 450 seconds at 750 캜.

14A to 14D show AFM images of 1 × 1 μm ² and FIGS. 14A to 14D show SEM images and FIGS. 1) shows the AFM side view, plan view and line-profile.

In Fig. 14, the reference is 50 nm in (a-2) and (c-2) and 200 nm in (e-2).

Fig. 15 shows the average density variation (error range: ± 5%) of Au nanostructures spontaneously formed on c-plane GaN according to the Au deposition thickness of 1 to 100 nm for 450 seconds at 750 ° C.

Figure 16 shows the average height and diameter variation (error range: ± 5%) of Au nanostructures spontaneously formed on c-plane GaN according to the Au deposition thickness of 1 to 100 nm for 450 seconds at 750 ° C .

17 shows an example of the structure of Au nanoclusters spontaneously formed at a heat treatment time of 450 seconds at a temperature of 750 DEG C for a deposition thickness of 3 nm fixed on c-plane GaN.

Figure 17 (a) is 2 × 2㎛ depicts a side view of the ^second AFM size, (a-1) is a plan view, FIG. 17 (a-2) is a cross-section along a horizontal line that appears shown in Fig. (A-1) - profile, and (a-3) shows the pre-filter transform (FFT) power spectrum.

18 shows an example of the structure of Au nanoclusters spontaneously formed at a heat treatment time of 450 seconds at a temperature of 750 DEG C for a deposition thickness of 5 nm fixed on c-plane GaN.

Figure 18 (b) is 3 × depicts a side view of the AFM 3㎛ ² size, (b-1) is a plan view, FIG. 18 (b-2) is a 18 (b-1) shown in FIG appears along the horizontal line Fig. 18 (b-3) shows a twice-magnified pre-filter transform (FFT) power spectrum.

19 shows an example of the structure of Au nanoclusters spontaneously formed at a heat treatment time of 450 seconds at a temperature of 750 DEG C for a deposition thickness of 10 nm fixed on c-plane GaN.

Figure 19 (c) is 5 × 5 ㎛ ² (C-1) is a plan view, FIG. 19 (c-2) shows a cross-sectional line-profile along the horizontal line indicated in (c-1) ) Shows a quadrupled magnified pre-filter transform (FFT) power spectrum.

FIG. 20 shows an example of the structure of Au nanoclusters spontaneously formed at a heat treatment time of 450 seconds at a temperature of 750 DEG C for a deposition thickness of 25 nm fixed on c-plane GaN.

20 (a) is an SEM image, (a-1) is a 20 × 20 μm ² size AFM image plan view, and FIG. 20 (a- (A-3) shows a pre-filter transform (FFT) power spectrum

FIG. 21 shows an example of the structure of Au nanoclusters spontaneously formed at a heat treatment time of 450 seconds at a temperature of 750 DEG C for a deposition thickness of 50 nm fixed on c-plane GaN.

21 (b) is a SEM image, (b-1) is a 20 × 20 μm ² size AFM image plan view, and FIG. 21 Section line-profile, and (b-3) shows a pre-filter transform (FFT) power spectrum

22 shows an example of the structure of Au nanoclusters spontaneously formed at a heat treatment time of 450 seconds at a temperature of 750 DEG C for a deposition thickness of 75 nm fixed on c-plane GaN.

22C shows a SEM image, FIG. 22C shows an AFM image plan view of 20 × 20 μm ² size, FIG. 22C shows a cross-sectional view along the horizontal line shown in FIG. 22C- (C-3) shows a pre-filter transform (FFT) power spectrum

23 shows an example of the structure of Au nanoclusters spontaneously formed at a heat treatment time of 450 seconds at a temperature of 750 DEG C for a deposition thickness of 100 nm fixed on c-plane GaN.

23 (d) shows an SEM image, (d-1) is a 20 × 20 μm ² size AFM image plane view, and FIG. 23 (d- (D-3) shows a pre-filter transform (FFT) power spectrum

Table 2 shows the average density, average height, side diameter (error range: ± 5%) of the Au nanostructures spontaneously formed on the c-plane GaN according to the Au deposition thickness of 3 to 100 nm for 450 seconds at 750 ° C., Lt; / RTI >

Deposition amount
[nm] Average height
[nm] Side diameter
[nm] density
[cm ^-2 ] 3 22.3 127.1 4.01 × 10 ⁹ 5 69.9 248.0 3.67 × 10 ⁸ 10 298.9 655.0 2.10 x 10 ⁷ 25 377.9 1369.4 1.44 × 10 ⁷ 50 535.2 1749.0 1.03 × 10 ⁷ 75 726.7 1942.9 8.69 × 10 ⁶ 100 765.9 2442.8 4.56 × 10 ⁶

Referring to FIGS. 17 to 23, when the deposition thickness is increased from 3 nm to 100 nm, the constitutional change of the Au nanostructure changes from a triangle to a hexagon and then to a polyhedron.

Further, the heat treatment temperature of 750 占 폚 is enough to cause Au crystallization, and Au nanostructure having a specific surface is formed.

In the surface energy, the surface energy distribution can be anisotropic and can vary depending on the crystallization direction. Therefore, the crystalline nanostructures are analyzed to be desirable to grow with a low surface energy.

In a given crystal plane, the free energy can be expressed as Equation 3 below.

(Equation 3)

은 깨진 결합의 수,

는 결합의 강도이고,

는 표면상의 원자의 밀도이다.here,

The number of broken bonds,

Is the strength of the bond,

Is the density of atoms on the surface.

의 Au에 대한 일반적으로 낮은 지수 {100}, {110} 및 {111}의 자유에너지는

= 4(

),

= 4.24(

), 및

= 3.36(

)로 산출될 수 있다. Due to the face-centered cubic structure of the Au crystal, the lattice constant

Generally, the free energies of the low index {100}, {110} and {111}

= 4 (

),

= 4.24 (

), And

= 3.36 (

). ≪ / RTI >

According to one embodiment of the present invention, the {111} planes have lower surface energies than the {100}, {110} planes and are analyzed to have other high-Miller indexed facets.

Thus, in order to minimize the surface energy, the growth of the nanostructure can be predicted to start with the low-miller index {111}, {100}, {110}, and then to be a high index. As evidence of this case, Au triangles with a height of ~ 2 nm and a diameter of ~ 70 nm are first fabricated at a low deposition thickness of 1 nm.

When the nanostructure size is relatively small, it may be a triangular-shaped Au nanostructure surrounded by a {111} plane.

Referring to Figures 14 (a) -14 (b), the size and density of the triangular nanostructures increase as the size uniformity improves during deposition from 1 nm to 2 nm.

Referring to Fig. 14 (c) and Fig. 17, an Au hexagonal shape is formed at a deposition thickness of 3 nm.

The hexagon may be formed according to a twin face model, which alternately includes a {111} face and convex and concave sides. Thus, the surface free energy of a hexagonal nanostructure can be lower than the surface free energy of other nanostructures.

Referring to FIG. 14 (d) and FIG. 18, when the deposition thickness is 5 nm, most of the Au nanostructures are formed in a hexagonal shape or in a polyhedral structure with a few larger nanostructures.

14 (e) and 19, when the deposition thickness is 10 nm, most of the Au nanostructures exhibit a polyhedral shape instead of a hexagonal shape.

Referring to FIGS. 20 to 22, when the deposition thickness is 25 to 75 nm, the Au nanostructure having the extended size has a hexagonal shape but a multi-faceted nanostructured shape.

Referring to FIG. 23, when the deposition thickness becomes 100 nm, a polyhedral structure having multiple faces is clearly shown.

Formation of the polyhedral structure is analyzed due to the increased volume.

Due to the greatly increased volume, the formation of nanostructures can be less sensitive to surface energy differences between various surfaces. This may result in multi-faceted nanostructures including {111}, {100}, {110} and other high Miller exponents. The diffusion of Au adsorbed atoms can vary greatly due to the influence of substrate properties such as surface step, crystal structure and surface energy. As a result, it was observed that the shape of Au nanoparticles on sapphire (0001) changed from a dome shape to a truncated hexagonal shape and from a truncated cone to a multifaceted dome shape.

On a GaAs substrate, when the deposition thickness is increased to 2 to 20 nm, the circular-dome-shaped small-sized Au nanoparticles appear to be changed into a large irregular shape.

In addition, the inter-diffusion between the substrate and the Au nanoparticles may also affect the nanoparticle composition. For example, the inter-diffusion between Au and Si can lead to structural changes in multi-faceted nanostructures to irregular nanoparticles.

Referring to FIGS. 15 and 16, as the deposition thickness increases, the density of the nanostructures decreases, but the size including the height and diameter increases.

Referring to Table 2, when increasing from 3 nm to 100 nm of deposition thickness, the average height and diameter are increased by a factor of 19 times to 765.9 (± 5%) nm and 34 times and 2442.8 (± 5%) nm respectively. On the other hand, the density is reduced by 800 times to 4.56 (± 5%) × 10 ⁶ cm ^-2 .

These structural changes of Au nanostructures can also be observed in FFT power spectra.

Referring to FIG. 14 (a-3), when 3 nm is deposited, the FFT spectrum shows a hexagonal pattern due to the formation of an Au hexagonal pattern.

Referring to Figure 14 (b-3), when 5 nm is deposited, the hexagonal pattern becomes brighter and smaller due to the increase of the nanostructure size.

As shown in Fig. 19 (c-3), when the deposition is increased to 10 nm, the FFT pattern is further contracted. Due to the constitutive change from hexagonal to polyhedral, the hexagonal pattern changed into a circular shape.

Also, referring to FIGS. 20-23, when deposited from 25 nm to 100 nm, the FFT spectrum is greatly reduced due to the increase in size.

FIG. 24 shows energy-dispersive X-ray spectroscopy (EDS) element characteristics of an Au nanocluster structure fabricated with a deposition thickness of 100 nm.

(A) is an SEM image, (b) is an Au phase map of EDS, (c) is an Au and Ga spectrum map of a region indicated by a green square in And a counter line-profile. (D) - (e) show the EDS spectra of the two regions shown in blue and red in (a), and (f) show a side view of the Au phase map in (b).

Referring to Figure 24, the Au phase map is analyzed to be very well matched to the original SEM image.

Also, as evidenced by the graph of the specific Au and Ga spectra and element strength shown in Figure 24 (c), the Au structure formed is analyzed to have high Au and low Ga concentration.

The Au distribution is clearly shown by the EDS energy spectrum of FIG. 24 (d) - FIG. 24 (e).

24 (d) - Fig. 24 (e), the Lα1 peak for Ga is observed at 1.105 keV. In addition, the M alpha 1 peak for Au is observed at 2.213 keV.

Conversely, the Au peak does not appear in the red-square of Fig. 24 (a). It is analyzed that all Au are diffused into the nanostructure.

Figure 25 shows a map of spontaneously formed Au nanostructures on c -plane GaN depending on the heat treatment temperature and deposition thickness.

In Figure 25 (a) - (d) is a plan view of the ^second AFM Size 0.25 × 0.25 ㎛, (e) the ^second size of 1 × 1 ㎛ AFM plan view, and (f) shows an SEM image.

25 is a graphical representation of various Au nanostructures matched to the growth conditions of both the heat treatment temperature (AT) and the deposition thickness (DA).

Since the heat treatment temperature leads to increased surface diffusion, the heat treatment temperature (AT) induced compositional change is aimed at minimizing the total surface energy through the desired surface diffusion.

Further, since Au can be crystallized at a sufficient heat treatment temperature (A), the surface free energy can be further reduced by the formation of a specific surface having a low surface energy.

According to the observation of the surface, the fabricated nanostructures can be separated into two systems: a multi-faceted system and a non-multi-faceted system.

In the deposition thickness (DA) effect, the nanostructural properties can be directly controlled by the Au deposition thickness, because the constitutive change is induced by a change in the surface energy distribution closely related to the nanostructure volume.

Another embodiment of the present invention is controlled by the role of heat treatment time in the formation of nanostructures.

FIGS. 26 to 30 show Au nanostructures prepared by spontaneous formation at a heat treatment temperature of 750.degree. C. for a fixed deposition thickness of 20 nm in accordance with each heat treatment time (AD) of 30 to 900 seconds.

Figs. 26 to 27 show Au nanostructures produced by spontaneous formation at a heat treatment temperature of 750 DEG C for a fixed deposition thickness of 20 nm and for each heat treatment time (AD) of 30 to 900 seconds.

26 shows Au nanostructures spontaneously formed during a heat treatment time (AD) of 30 seconds at a heat treatment temperature of 750 DEG C for a fixed deposition thickness of 20 nm.

(a-1) shows an AFM plan view of a size of 10 × 10 μm ² , and (a-2) shows a cross-sectional view along the horizontal line shown in (a-1) Line profile, and (a-3) shows the EDS Au phase map vs. SEM image.

(a-3), the red line-profile represents the Au intensity distribution.

(a-4) shows an enlarged Au phase map and Au and Ga count line-profile, and (a-5) shows an EDS spectrum of an area enlarged in (a-3).

Figure 27 shows Au nanostructures spontaneously formed during a heat treatment time (AD) of 90 seconds at a heat treatment temperature of 750 占 폚 for a fixed deposition thickness of 20 nm.

(b-1) shows an AFM plan view of a size of 10 10 ² 탆 ² , (b-2) shows a cross-sectional view along a horizontal line shown in (b-1) Line profile, and (b-3) shows an EDS Au phase map vs. SEM image.

(b-3), the red line-profile shows the Au intensity distribution.

(b-4) shows an enlarged Au phase map and Au and Ga count line-profile, and (a-6) shows an EDS spectrum of an area enlarged in (b-3).

28 shows Au nanostructures spontaneously formed during a heat treatment time (AD) of 250 seconds at a heat treatment temperature of 750 DEG C for a fixed deposition thickness of 20 nm.

(a-1) shows an AFM plan view of a size of 10 × 10 μm ² , and (a-2) shows a cross-sectional view along the horizontal line shown in (a-1) Line profile, and (a-3) shows the EDS Au phase map vs. SEM image.

(a-3), the red line-profile shows the Au intensity distribution.

29 shows Au nanostructures spontaneously formed during a heat treatment time (AD) of 450 seconds at a heat treatment temperature of 750 DEG C for a fixed deposition thickness of 20 nm.

(b-1) shows an AFM plan view of a size of 10 10 ² 탆 ² , (b-2) shows a cross-sectional view along a horizontal line shown in (b-1) Line profile, and (b-3) shows an EDS Au phase map vs. SEM image.

(b-3), the red line-profile shows the Au intensity distribution.

Figure 30 shows Au nanostructures spontaneously formed during a heat treatment time (AD) of 900 seconds at a heat treatment temperature of 750 캜 for a fixed deposition thickness of 20 nm.

(c-1) shows an AFM plan view of a size of 10 10 ² 탆 ² , (c-2) shows a cross-sectional view along the horizontal line shown in (c-1) Line profile, and (c-3) shows the EDS Au phase map vs. SEM image.

(c-3), the red line-profile shows the Au intensity distribution.

FIG. 31 shows the average height, diameter, and average density variation (error range: 0 to 100 nm) of the Au nanostructures spontaneously formed at a heat treatment time (AD) of 250 to 900 seconds at a heat treatment temperature of 750 DEG C for a fixed deposition thickness of 20 nm. ± 5%).

Referring to Figures 26 to 31, the initial Au film is irregular nano clusters through surface diffusion, resulting in an irregular grain state (dewetted).

Referring to Figure 26 (a), the nanoclusters formed due to insufficient heat treatment time are not well grown.

When the heat treatment time is increased to 90 seconds, the irregular Au nanocluster gradually evolves into a polyhedron and becomes polyhedron nanoparticles as shown in FIG. 27 (b).

Referring to FIGS. 28 to 31, when the annealing time (AD) is 250 seconds or more, the nanostructure is formed with a well-grown polyhedral shape, the size of the nanostructure is increased, and the density is decreased.

Evolution of the size induced by the heat treatment temperature is analyzed to be attributed to Ostwald ripening by the surface free energy minimization mechanism.

Larger nanostructures can be decomposed into smaller nanostructures as they have lower surface energies, and can be absorbed in larger nanostructures to lower total surface energy. According to one embodiment of the present invention, in the Ostwald aging, the average radius (R _m ) of the nanostructure according to the heat treatment time (t) can be expressed by the following equation.

(Equation 4)

Where R ₀ is the initial average radius, and K ^* is the fixed temperature constant.

The average radius of the nanostructure according to the heat treatment time can be controlled by the relationship expressed by Equation (4).

As shown in the equation, the average size of the nanostructures may gradually increase as the annealing time (AD) is prolonged.

Referring to FIG. 31, at 250 seconds, the average height of the nanostructure is 250.3 (+/- 5%) nm and the side diameter is 669.9 (+/- 5%) nm. At 450 (± 5%) seconds, both the average height and diameter increased, and the average height increased to 276.3 (± 5%) nm and the diameter increased to 686.4 nm (± 5%).

Table 3 shows the average height, side diameter, density (error range: ± 5%) of Au nanostructures produced according to the heat treatment time of 250 nm to 900 seconds at 750 ° C with a 20 nm Au deposition thickness and a heating rate of 10 ° C / .

Time
[s] Average height
[nm] Side diameter
[nm] density
[cm ^-2 ] 250 250.3 669.9 9.73 × 10 ⁷ 450 276.3 686.4 9.40 x 10 ⁷ 900 321.8 734.3 6.25 × 10 ⁷

According to one embodiment of the present invention, the amount of small nanoparticles was reduced due to adsorption between the nanoparticles at a heat treatment time of 900 ((± 5%) seconds.

The mean height increased to 321.8 (± 5%) nm and the diameter increased to 734.3 (± 5%) nm. At this time, the density is decreased to continue to 250 (± 5%) seconds, if 9.73 (± 5%) × 10 7 cm from ^-2 450 (± 5%) when the second 9.40 (± 5%) × 10 7 cm -2 And decreased to 6.25 (± 5%) × 10 ⁷ cm ^{- 2} at 900 sec.

Figs. 26 (a-3) and 27 (b-3) show an EDS Au image map and an SEM image. The Au nanoparticles in the SEM image agree well with the Au intensity distribution.

26 (a-4) - In Fig. 27 (b-4), the Ga and Au line-profiles show enlarged EDS mapping. Only Au peaks were observed at Au nanoparticles.

As shown in Figs. 26 (a-5) and 27 (a-6), this was also confirmed in the Au EDS spectra of two regions. In particular, only Au peaks were observed in the spectrum of Au nanostructures. On the other hand, Au was not observed in the background as shown in Fig. 27 (a-6).

According to one embodiment of the present invention, the gold nanoparticles formed on the GaN by controlling the growth conditions including the heat treatment temperature, the deposition amount, and the heat treatment time may be changed into Au triangular, nanorod, hexagonal, And a polyhedral nanostructure shape.

At the change of the annealing temperature, the island form of Au insect shape was formed first at 350 ℃ based on the Boomer - Weber growth model. As the temperature increases from 450 to 750 ° C., the nanostructure of the insect-shaped nanostructures gradually changes into nanostructured nanorods and hexagons due to the influence of surface diffusion and Au crystallization with increasing temperature.

At the heat treatment temperature of 800 ° C, most of the nanostructures finally show a hexagonal shape.

For variations depending on the deposition amount, Au triangles first appear at Au deposition thicknesses of 1 and 2 nm.

In addition, Au triangles are changed to hexagons by increasing the Au deposition thickness of 3 and 5 nm.

 At 10 nm Au deposition thickness, the Au nanostructures with greatly expanded volume were preferred to be polyhedral.

In the case of Au deposition of 25 to 100 nm, the polyhedral nanostructure was mostly formed. Irregular Au nanostructures were observed at relatively short annealing times in the annealing time, and formation of nanostructures with polyhedral structure was observed at the increased annealing time. Based on Ostwald aging, the size of the nanoparticles gradually increased due to the desorption of small nanoparticles, while the density decreased.

Claims (12)

delete delete delete A method for controlling the growth of Au nanostructures on GaN by depositing Au in a pulse-raising deposition chamber and spontaneously forming by heat treatment,
The deposition thickness is controlled to be within ± 5% of the thickness of 3 nm, and the thickness, thickness, and thickness of the grown Au nanostructure are controlled by the deposition thickness of the Au, the heat treatment temperature and the heat treatment time, And the heat treatment temperature is controlled within the range of 550 ° C. to 850 ° C. and the heat treatment time is controlled within the range of 30 to 900 seconds,
The deposition thickness was set to 3 (± 5%) nm, the heat treatment temperature was set to 550 ° C, and the annealing time was maintained at 450 (± 5%) sec to adjust the shape of the grown Au nanostructure to a multi- The hexagonal nanostructures may be controlled to have a mixed shape,
Or the deposition thickness is set to 3 (± 5%) nm, the heat treatment temperature is set to 650 to 800 ° C, and the annealing time is maintained at 450 (± 5% Wherein the growth of the Au nanostructure is controlled by a structure of GaN.
A method for controlling the growth of Au nanostructures on GaN by depositing Au in a pulse-raising deposition chamber and spontaneously forming by heat treatment,
The deposition thickness is controlled to be within ± 5% of the thickness of 3 nm, and the thickness, thickness, and thickness of the grown Au nanostructure are controlled by the deposition thickness of the Au, the heat treatment temperature and the heat treatment time, And the heat treatment temperature is controlled within the range of 550 ° C. to 850 ° C. and the heat treatment time is controlled within the range of 30 to 900 seconds,
The annealing temperature was increased from 550 ° C. to 650 ° C. to maintain the density of the grown Au nanostructure at a value of 3 (± 5%) nm, maintaining the annealing time at 450 (± 5%) seconds, 1.56 (± 5%) times.
Alternatively, the density of the grown Au nanostructure was maintained at 4.84 (± 5%) by maintaining the deposition thickness at 3 (± 5%) nm and the heat treatment time at 450 ± 5%) × 10 ⁹ cm ^-2 ,
The density of the grown Au nanostructure was maintained at 4.0 ((5%)) seconds, and the heat treatment time was maintained at 450 (± 5%) seconds, + - 5%) x 10 < ⁹ > cm < ^{-2 &} gt ;.
delete delete delete A method for controlling the growth of Au nanostructures on GaN by depositing Au in a pulse-raising deposition chamber and spontaneously forming by heat treatment,
The shape, average height, side diameter and density of the grown Au nanostructure are controlled by the deposition thickness of the Au, the heat treatment temperature of the heat treatment process, and the heat treatment time, wherein the deposition thickness is in the range of 1 nm to 2 nm And the heat treatment temperature is controlled in a range of 550 ° C. to 850 ° C. and the heat treatment time is controlled in a range of 30 to 900 seconds,
The deposition thickness is increased from 1 (± 5%) nm to 2 (± 5%) nm while the heat treatment temperature is maintained at 650 ° C. and the heat treatment time is maintained at 450 (± 5% Wherein the Au nanostructure is formed in a triangular shape and the size and density of the Au nanostructure are controlled to be increased.
A method for controlling the growth of Au nanostructures on GaN by depositing Au in a pulse-raising deposition chamber and spontaneously forming by heat treatment,
The thickness, thickness, thickness and thickness of the grown Au nanostructure are controlled by the deposition thickness of the Au, the heat treatment temperature of the heat treatment process, and the heat treatment time, And the heat treatment temperature is controlled within the range of 550 ° C. to 850 ° C. and the heat treatment time is controlled within the range of 30 to 900 seconds,
Wherein the grown Au nanostructures are controlled to have a polyhedral shape by maintaining the deposition thickness at 10 nm and the annealing temperature at 650 ° C. and the annealing time at 450 (± 5%) seconds. Methods for growth control of nanostructures.
A method for controlling the growth of Au nanostructures on GaN by depositing Au in a pulse-raising deposition chamber and spontaneously forming by heat treatment,
The shape, average height, side diameter and density of the grown Au nanostructure are controlled by the deposition thickness of the Au, the heat treatment temperature of the heat treatment process, and the heat treatment time, wherein the deposition thickness is in the range of 3 nm to 100 nm And the heat treatment temperature is controlled in a range of 550 ° C. to 850 ° C. and the heat treatment time is controlled in a range of 30 to 900 seconds,
(5%) at 22.3 (+/- 5%) nm, wherein the annealing temperature is maintained at 650 < 0 > C and the annealing time is maintained at 450 nm, the side diameter is increased from 127.1 (± 5%) nm to 2442.8 (± 5%) nm and the density of the grown Au nanostructures is 4.01 (± 5%) × 10 ⁹ to 4.56 + - 5%) x 10 < ⁶ > cm < ^{-2 &} gt ;.
5. The method of claim 4,
Wherein the average radius of the nanostructure according to the heat treatment time is controlled according to the following equation.

here,

Is the initial average radius,

Is a fixed temperature constant

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