JP2720532B2 - Blue semiconductor light emitting device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blue semiconductor light emitting device that is expected to be used as a light source for display, measurement, optical information processing, and the like.

2. Description of the Related Art Many II-VI group compound semiconductors have wide gap direct transition type materials and are promising as blue light emitting elements.
In addition, recent advances in crystal growth technology have made it possible to produce high-quality single crystals.For example, ZnS and ZnSe have been shown to exhibit high luminous efficiency by photoexcitation or electron beam excitation, and laser oscillation has also been confirmed. ing. On the other hand, LED (light emitting diode) and L
D (laser diode). These are Pn in the crystal
The device forms a junction and emits light by current injection excitation. The device is extremely miniaturized. However
In the case of II-VI compound semiconductors, the doping of impurities is not yet sufficient, and no crystal that can be practically applied to an injection-excitation light-emitting device, such as formation of a Pn junction and low resistance of the crystal, has been obtained. Therefore, at present, it is difficult to obtain highly efficient light emission only by light excitation or electron beam excitation. However, since these excitation sources are large, they have a drawback that they also become large as light emitting devices.

Problem to be Solved by the Invention The present invention has been made in view of the above problems, and has as its object to provide a small-sized blue semiconductor light emitting device by using ultraviolet light generated by gas discharge as excitation light. .

Means for solving the problem A voltage is applied to the inside of a discharge cell filled with a specific rare gas, and ultraviolet light emitted when the discharge is started is used as excitation light, which is applied to a II-VI group compound semiconductor crystal. Thus, a small-sized blue semiconductor light emitting device is realized by a configuration for obtaining blue light emission by light excitation. That is, in the blue semiconductor light emitting device of the present invention, a rare gas or a fluoride gas thereof is sealed in a space between an outer wall formed of ceramic and a window material that transmits blue light, and a voltage is applied to the gas. II-VI compound exhibiting blue fluorescence in which a discharge cell having electrodes formed thereon and a dielectric multilayer reflective film having a reflectance of 90% or more formed as a resonance mirror on both end surfaces parallel to the light extraction surface inside the cell And a semiconductor crystal. Furthermore, in the present invention, a rare gas or a fluoride gas thereof is sealed in a space between an outer wall formed of ceramic and a window material made of any of sapphire, CaF ₂ , SrF ₂ , and (CaSr) F _2. A blue semiconductor light emitting device, comprising: a discharge cell in which an electrode for applying a voltage to the gas is formed; and an excitation light emitting crystal provided outside the cell.

According to the action present invention, the generation of the excitation light by discharge cells of a few tens of mm ³ about volume becomes possible, a conventional excitation light source, and can He-Cd laser or an excimer laser as compared significantly downsized Become.

Examples Hereinafter, the present invention will be described in detail based on examples shown in the drawings.

Embodiment 1 FIG. 1 shows a configuration of a blue semiconductor fluorescent device. For example, an iodine-doped ZnS light emitting layer 1 is adhered to the quartz glass light extraction window 2, and, for example, a Xe gas 7 is sealed inside together with the cell outer wall 3 formed of ceramic.
Inside the cell outer wall 3, two types of dielectric multilayer reflection films 4, 4 'made of, for example, SiO ₂ / TiO ₂ and positive and negative electrodes 5, 6 are formed in advance. The dielectric multilayer reflective film (A) 4 is
The dielectric multilayer reflective film (B) 4 'responds to ultraviolet light emitted during the discharge of the Xe gas, to blue light which is fluorescent.
It is manufactured to have a high reflectance of 90% or more. The entire cell is mounted on a heat sink 8. In this device, when a voltage of 200 V is applied to the positive and negative electrodes 5, 6, Xe
The gas starts discharging, and ultraviolet light having a peak near a wavelength of 168 nm is emitted. The ultraviolet light is efficiently absorbed in the ZnS light emitting layer 1 while repeating multiple reflections in the cell by the dielectric multilayer reflective film (A) 4, and has a peak near a wavelength of 470 nm due to fluorescence. Emit blue light. This blue light is directly extracted from the quartz glass light extraction window 2 to the outside, and the light emitted in the direction opposite to the quartz glass light extraction window 2 also emits the dielectric multilayer reflective film (B).
The light is reflected by 4 'and efficiently taken out.

Embodiment 2 FIG. 2 shows the configuration of a photo-excitation blue semiconductor laser device. The quartz glass light extraction window 2 is provided with the light extraction window 2
A ZnSe single crystal 11 on which a dielectric multilayer reflection film resonant mirror 12 made of, for example, SiO ₂ / TiO ₂ is fixed on both end faces parallel to the Xe gas 7 inside the cell outer wall 3 formed with ceramic. Enclosed. The resonance mirror 12 is manufactured so that the reflectance is about 90% or more with respect to a wavelength of about 470 nm, which is the fluorescence of the ZnSe single crystal. Inside the cell, a dielectric multilayer reflective film 4 made of, for example, SiO ₂ / TiO ₂ is previously provided.
And the positive and negative electrodes 5 and 6 are formed. The dielectric multilayer reflection film 4 is manufactured so as to have a high reflectance of 90% or more with respect to ultraviolet light emitted when the Xe gas 7 is discharged. The entire cell is mounted on a heat sink 8. In this apparatus, when a voltage of about 200 V is applied between the positive and negative electrodes 5 and 6, the Xe gas 7 starts discharging and emits ultraviolet light having a peak near a wavelength of 168 nm. The ultraviolet light is repeatedly reflected multiple times inside the cell by the dielectric multilayer reflection film 4.
It is efficiently absorbed in the ZnSe single crystal 11. In addition, at the end face where the resonance mirror 12 is formed, the reflectivity for ultraviolet light due to discharge is smaller than the original crystal face, so that the ZnSe single crystal is used.
The amount of ultraviolet light incident on 11 can be increased. Although laser oscillation requires a strong light density, the present apparatus has a high excitation efficiency, so that sufficient fluorescence can be obtained, and laser oscillation can be performed with a high reflectance of the resonance mirror 12. The laser light having a wavelength of about 470 nm is extracted to the outside through the quartz glass light extraction window 2.

Third Embodiment FIG. 3 shows the configuration of a photo-excitation blue semiconductor laser device. The cell constituted by the cell outer wall 3 made of ceramic and the quartz glass light extraction window _{2 is}
Is separated into two chambers by a partition plate 13 and the upper part is vacuum and both ends parallel to the light extraction window 2 are provided with a dielectric multilayer reflection film resonant mirror.
The ZnSe single crystal 11 on which 12 is formed is fixed. The resonance mirror 12 is formed so that the reflectance of the ZnSe single crystal 11 at about 470 nm, which is the fluorescence of the ZnSe single crystal 11, is 90% or more. Xe gas is sealed in the lower part, and positive and negative electrodes 5 and 6 are formed. Further, a dielectric multilayer reflective film 4 made of, for example, SiO ₂ / TiO ₂ is formed inside the cell over the upper and lower chambers. The dielectric multilayer reflective film 4 is formed so as to have a high reflectance of 90% or more with respect to ultraviolet light emitted upon discharge of Xe gas. The entire cell is mounted on a heat sink 8. In this apparatus, when a voltage of about 200 V is applied between the positive and negative electrodes 5 and 6, the Xe gas 7 starts discharging, and ultraviolet light having a wavelength of about 168 nm is emitted. CaF
Since the two partition plates 13 are transparent to ultraviolet light, the ultraviolet light is efficiently absorbed by the dielectric multilayer reflective film 4 in the ZnSe single crystal 11 while repeating multiple reflections inside the cell, as in the second embodiment. Is done. In addition, at the end face on which the resonance mirror 12 is formed, the amount of ultraviolet light incident on the ZnSe single crystal 11 can be increased since the reflectivity for ultraviolet light due to discharge is smaller than that of the original crystal plane. Although laser oscillation requires a strong light density, the present apparatus has a high excitation efficiency, so that sufficient fluorescence can be obtained, and laser oscillation can be performed with a high reflectance of the resonance mirror 12. Further, in this device, the semiconductor crystal and the discharge region are spatially separated. In the case of Embodiment 2, Zn
Since the Se single crystal 11 and the resonance mirror 12 are directly exposed during the discharge, they are gradually eroded, and it is difficult to ensure the reliability.
However, in this embodiment, the problem can be solved and high reliability can be obtained. In all the examples, the light emitting material
Although ZnS and ZnSe were used, any II-VI compound semiconductor may be used. Although Xe was used as the discharge gas, other gases that emit ultraviolet light as shown in the following table may be used.

Further, sapphire, SrF ₂ , or (CaSr) F ₂ may be used as the light extraction window or the partition plate depending on the wavelength of ultraviolet light.

Effects of the Invention According to the present invention, a blue semiconductor fluorescent device and a blue semiconductor laser device having a size similar to that of an LED or an LD and capable of obtaining a practically sufficient light luminance, and a high reliability thereof can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a blue semiconductor fluorescent device according to a first embodiment of the present invention, FIG. 2 is a configuration diagram of a photoexcited blue semiconductor laser device according to the second embodiment, and FIG. FIG. 1 is a configuration diagram of a photo-excitation type blue semiconductor laser device according to an embodiment. 1 ... ZnS light emitting layer, 2 ... Quartz glass light extraction window, 3
…… Cell outer wall, 4 …… 4 '. Dielectric multilayer reflective film, 5 ...
Positive electrode, 6 ...... negative electrode, 7 ...... Xe gas, 8 ...... heatsink, 11 ...... ZnSe single crystal, 12 ...... dielectric multilayer reflection film resonator mirror, 13 ...... CaF ₂ partition plate.

Claims (3)

(57) [Claims] A discharge cell in which a rare gas or a fluoride gas thereof is sealed in a space between an outer wall formed of ceramic and a window material transmitting blue light, and an electrode for applying a voltage to the gas is formed; A blue-fluorescent II-VI compound semiconductor crystal having a dielectric multilayer reflection film having a reflectance of 90% or more formed as a resonance mirror on both end surfaces parallel to the light extraction surface inside the cell. Characteristic blue semiconductor light emitting device. 2. A rare gas or a fluoride gas thereof is sealed in an outer wall formed of ceramic and a space of a window material made of any one of sapphire, CaF2, SrF2 and (CaSr) F2, and a voltage is applied to the gas. A blue semiconductor light emitting device comprising: a discharge cell in which an electrode to be applied is formed; and an excitation light emitting crystal provided outside the cell. 3. A dielectric multilayer reflective film having a reflectivity of at least 90% for at least one of ultraviolet light and blue fluorescent light emitted by discharge is formed inside a discharge cell. 3. The blue semiconductor light emitting device according to item 1 or 2.