KR20190140330A - Solar cell formed by bonding - Google Patents

Abstract

The present invention relates to a multijunction photovoltaic cell formed by wafer bonding. More specifically, the multijunction photovoltaic cell comprises: heterojunction photovoltaic cell units including an III-V compound semiconductor; and a base photovoltaic cell formed with a semiconductor including silicon disposed at lower portion of the arrangement of the photovoltaic cell units. The lower portion of the heterojunction photovoltaic cell units and an upper portion of the base photovoltaic cell are formed of materials, which may be bonded to each other by wafer bonding. The heterojunction photovoltaic unit cells form a constant array on the base photovoltaic cell. Furthermore, the heterojunction photovoltaic unit cells of the multijunction photovoltaic cell include a first photovoltaic cell, a second photovoltaic cell disposed under the first photovoltaic cell, and a first tunnel barrier disposed between the first and second photovoltaic cells.

Description

Solar cell using bonding {Solar cell formed by bonding}

The present invention relates to a solar cell, and more particularly to a solar cell comprising a III-V compound solar cell.

Solar cells are formed to convert light energy into electrical energy. In general, a solar cell is composed of a P-type semiconductor and an N-type semiconductor, and when light shines, electric charges move to generate a potential difference.

In particular, III-V compound semiconductor solar cells are advantageous for high magnification and have high efficiency. In addition, III-V compound semiconductor solar cells can stack solar cells having various absorption bands, thereby making a solar cell having a multi-junction tandem structure more advanced than a single junction structure. Can be.

Conventional multi-junction solar cells have been implemented as stacked solar cells of GaInP solar cells (top cells) / GaAs solar cells (middle cells) / Ge solar cells (bottom cells) using a lattice mismatched growth technique. However, the lattice constants between the solar cells were inconsistent and a layer was needed to reduce the inconsistent lattice constant. In detail, the layer that reduces the mismatch of lattice constant may be composed of III-V material having the same lattice constant as the GaAs substrate and having an energy band gap of less than 1.0 eV. That is, a grading layer formed of a GaInP compound semiconductor having a thickness of 5.0 μm or more, which is unnecessary for photoelectric efficiency, existed between solar cells.

Since the indium (In) included in the grading layer formed of the GaInP compound semiconductor and the GaInP compound semiconductor layer constituting the GaInP top cell is an expensive material, there is a problem in that the cost of manufacturing a multi-junction solar cell increases.

In addition, in order to manufacture a multi-junction solar cell, in addition to the time required for epi growth in the process of epitaxial growth of forming GaInP solar cell (top cell), GaAs solar cell (middle cell) and grading layer by organometallic chemical vapor deposition In order to prepare for epi growth, there was a problem in that a lot of time and cost were generated in the exaggeration of temperature increase and temperature reduction after completion of epi growth.

One object of the present invention is to reduce the consumption of expensive indium (In) in a multi-junction solar cell, to provide a multi-junction solar cell with improved light conversion efficiency.

Another object of the present invention is to provide a method for manufacturing a multi-junction solar cell which is reduced in time and cost consumed in the method of manufacturing a multi-junction solar cell.

The present invention relates to a multi-junction solar cell using wafer bonding. In detail, the multi-junction solar cell of the present invention includes a double-junction solar cell unit comprising a III-V compound semiconductor; And a base solar cell formed of a semiconductor including silicon disposed under the array of solar cell units, wherein a lower portion of the double junction solar cell unit and an upper portion of the base solar cell are coupled to each other by wafer bonding. And a plurality of double junction solar cell units on the base solar cell to form a constant array. Further, the double junction solar cell unit of the multi-junction solar cell of the present invention, the first solar cell; A first solar cell and a second solar cell disposed below; And a first tunnel barrier disposed between the first solar cell and the second solar cell.

In an embodiment, the first solar cell of the double junction solar cell unit is formed of an AlGaAs compound semiconductor.

In an embodiment, the second solar cell of the double junction solar cell unit is formed of a GaAs compound semiconductor.

In an exemplary embodiment, a second tunnel barrier may be provided between the double junction solar cell unit and the base solar cell.

In an embodiment, the surface of the base solar cell exposed between the array of double junction solar cell units has a predetermined shape.

In an embodiment, the base solar cell is characterized in that formed of a silicon solar cell.

In an embodiment, the base solar cell is characterized in that formed of a Si / SiGe double junction solar cell.

In an embodiment, it characterized in that it comprises a light transmitting layer having a condenser lens corresponding to the arrangement of the double junction solar cell unit.

In addition, in the multi-junction solar cell manufacturing method of the present invention, preparing a base solar cell; Sequentially growing a sacrificial layer, a first solar cell layer, a first tunnel barrier layer, and a second solar cell layer on the growth substrate to form a double junction solar cell layer including a III-V compound semiconductor; Repeating the step of forming the double junction solar cell layer a plurality of times to form a multilayer double junction solar cell layer; Etching the double-junction solar cell layer positioned on the top of the multilayer double-junction solar cell layer with a first etching solution in a predetermined pattern to form an array of double-junction solar cell units and units; Coupling the double junction solar cell unit and the array of units to a base solar cell by wafer bonding; And etching the sacrificial layer adjacent to the second solar cell of the double junction solar cell layer positioned on the top with the second etching solution. In detail, in the etching of the sacrificial layer, the double junction solar cell unit and the array of units are separated from the multilayer double junction solar cell, and the forming of the array of the double junction solar cell unit and the unit is performed from the sacrificial layer. It is characterized in that for repeating the etching a plurality of times.

In an embodiment, in the preparing of the base solar cell, the base solar cell is formed of a silicon solar cell.

In an embodiment, in the preparing of the base solar cell, the base solar cell is formed of a Si / SiGe double junction solar cell.

In an embodiment, the preparing of the base solar cell may further include forming a second tunnel barrier on the base solar cell.

In an embodiment, in the forming of the double junction solar cell layer, the sacrificial layer is formed of an AlAs layer.

In an embodiment, in the forming of the double junction solar cell layer, the first solar cell layer is formed of an AlGaAs compound semiconductor.

In an embodiment, in the forming of the double junction solar cell layer, the second solar cell layer is formed of a GaAs compound semiconductor.

In example embodiments, in the forming of the double junction solar cell unit and the array of units, the first etching solution may etch the first solar cell layer, the first tunnel barrier layer, and the second solar cell layer. do.

The method may further include etching the surface of the base solar cell between the array of the double junction solar cell units after the etching of the sacrificial layer.

In an embodiment, the method may further include stacking a light transmitting layer including a condenser lens corresponding to the arrangement of the double junction solar cell unit.

In the multi-junction solar cell of the present invention, it is possible to provide a first solar cell in which expensive indium is excluded, and to reduce the consumption of indium by excluding a grading layer formed of a GaInP compound semiconductor, thereby reducing costs.

In addition, in the method of manufacturing a multi-junction solar cell, a step of forming a double-junction solar cell layer on a growth substrate is repeated a plurality of times, including forming a multi-junction solar cell layer of a multi-junction solar cell. It can save growth time and cost.

In addition, the double-junction solar cell layer is etched to form a double-junction solar cell unit, and by bonding the double-junction solar cell unit to the base solar cell in sequence by wafer bonding, the sacrificial layer is etched to double the double-junction solar cell layer. Separate the junction solar cell unit. Thus, by repeating the steps of forming a double-junction solar cell unit of each layer of the double-junction solar cell layer formed on one growth substrate to etching the sacrificial layer to manufacture a multi-junction solar cell, it is coupled to the base solar cell Therefore, there is an effect of reducing the growth substrate cost consumed in producing multi-junction solar cells.

1 is a conceptual diagram illustrating an embodiment of a multi-junction solar cell of the present invention.
2 is a partially enlarged view of a portion A of FIG. 1.
3 and 4 are conceptual views showing a modification of the multi-junction solar cell of the present invention.
5 is a conceptual diagram illustrating a method of manufacturing a multi-junction solar cell of the present invention.
6 is a conceptual diagram illustrating a modification of the manufacturing method of the multi-junction solar cell of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments disclosed herein will be described in detail with reference to the accompanying drawings, and different embodiments may be assigned the same or similar reference numerals for the same or similar components, and description thereof will be replaced with the first description. As used herein, the singular forms "a", "an" and "the" include plural forms unless the context clearly indicates otherwise. The suffix "part" for components used in the following description is given or mixed in consideration of ease of specification, and does not have meanings or roles that are distinguished from each other. In addition, in describing the embodiments disclosed herein, when it is determined that the detailed description of the related known technology may obscure the gist of the embodiments disclosed herein, the detailed description thereof will be omitted. In addition, it should be noted that the accompanying drawings are only for easily understanding the embodiments disclosed in the present specification and are not to be construed as limiting the technical spirit disclosed in the present specification by the accompanying drawings.

Also, when an element such as a layer, region or substrate is referred to as being on another component "on", it is to be understood that it may be directly on another element or intermediate elements may be present therebetween. There will be.

Hereinafter, the multi-junction solar cell of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a conceptual diagram illustrating an embodiment of a multi-junction solar cell 100 of the present invention, and FIG. 2 is a partially enlarged view of portion A of FIG. 1.

Referring to FIGS. 1 and 2, the multi-junction solar cell 100 of the present invention has a high light absorption rate compared to a silicon solar cell including a III-V compound semiconductor having a direct transition band gap. In addition, the multi-junction solar cell 100 of the invention stacks the double-junction solar cell unit 110 and the base solar cell 120 including the first solar cell 111, the second solar cell 112 and the solar light It can be made to absorb the full wavelength to produce electricity.

The band gap may be reduced in order of the first solar cell 111, the second solar cell 112, and the base solar cell 120. That is, the first solar cell 111 having the largest band gap is positioned at the top, and thus may absorb sunlight first. Subsequently, the second solar cell 112 having an intermediate band gap is positioned at the center, and the base solar cell 120 having the smallest band gap is located at the bottom thereof to sequentially absorb sunlight.

In detail, the first solar cell 111 absorbs sunlight having a wavelength of 300 to 670 nm to produce electricity, and the second solar cell 112 absorbs sunlight having a wavelength of 500 to 890 nm to produce electricity. Since the base solar cell 120 absorbs sunlight having a wavelength of 650 to 1180 nm to produce electricity, the multi-junction solar cell 100 can efficiently use the entire wavelength of the solar light by dividing it into several parts. Accordingly, the multijunction solar cell 100 may obtain higher conversion efficiency than the single junction solar cell.

Hereinafter, the multi-junction solar cell 100 includes a unit body 110 and a base solar cell 120 of a double junction solar cell.

The unit 110 of the double junction solar cell may include a III-V compound semiconductor. The first solar cell 111 of the double junction solar cell unit 110 may be formed of an AlGaAs compound semiconductor, and the second solar cell 112 may be formed of a GaAs compound semiconductor. Since the first solar cell 111 is formed of an AlGaAs compound semiconductor and the second solar cell 112 can eliminate the lattice constant mismatch with the GaAs compound semiconductor, the solar cell has a thickness of 5.0 um or more that is unnecessary for photoelectric efficiency between the solar cells. A grading layer formed of a GaInP compound semiconductor may be excluded. Furthermore, the cost of manufacturing a multi-junction solar cell can be reduced since the grading layer formed of the GaInP compound semiconductor and the expensive indium (In) included in the GaInP compound semiconductor layer constituting the conventional GaInP solar cell are excluded. Can be.

In an embodiment, the first solar cell 111 formed of the AlGaAs compound semiconductor may be formed of the first conductive semiconductor layer 111a and the second conductive semiconductor layer 111b. The first conductive semiconductor layer 111a and the second conductive semiconductor layer 111b may each include a plurality of layers. In addition, the first solar cell 111 may be formed to have a thickness in the range of 0.9 to 2.0 μm to produce electricity with sunlight having a wavelength of 300 to 670 nm.

In addition, the second solar cell 112 formed of the GaAs compound semiconductor may be formed of the first conductive semiconductor layer 112a and the second conductive semiconductor layer 112b. The first conductive semiconductor layer 112a and the second conductive semiconductor layer 112b may each include a plurality of layers. In addition, the second solar cell 112 may be formed to have a thickness ranging from 0.6 to 1.5 μm to produce electricity with sunlight having a wavelength of 500 to 890 nm.

Meanwhile, the base solar cell 120 may be disposed under the double junction solar cell unit 110 and be formed of a semiconductor including silicon. Similar to the first solar cell 111 and the second solar cell 112 described above, the first conductive semiconductor layer 120a and the second conductive semiconductor layer 120b may be formed, and the first conductive semiconductor layer may be formed. 120a and the second conductive semiconductor layer 120b may each include a plurality of layers. In addition, the base solar cell 120 may be formed to have a thickness in the range of 150 to 500 ㎛ to produce electricity with sunlight of 650 to 1180 nm wavelength. Further, the base solar cell 120 may be formed of a Si / SiGe double junction solar cell. Thus, the multi-junction solar cell 100 may have a higher efficiency.

In addition, the first conductive semiconductor layer may be an n-type semiconductor layer, and the second conductive semiconductor layer may be a p-type semiconductor layer. However, the present invention is not necessarily limited thereto, and an example in which the first conductivity type is p-type and the second conductivity type is n-type is also possible.

Meanwhile, the multi-junction solar cell 100 includes a first tunnel barrier 111 and a second tunnel barrier 130. The first tunnel barrier 113 may be disposed between the first solar cell 111 and the second solar cell 112. Thus, the first solar cell 111 and the second solar cell 112 may be connected in series with each other.

In addition, a second tunnel barrier 130 may be disposed between the unit body 110 and the base solar cell 120 of the double junction solar cell. Thus, the unit body 110 and the base solar cell 120 of the double junction solar cell may be connected in series with each other.

Since the first tunnel barrier 113 and the second tunnel barrier 130 move carriers through the tunneling effect, a thickness for optimal probability of tunneling should be formed, and the thickness for optimal probability of tunneling is 0.1 to It may have a range of 5 nm.

In addition, the unit body 110 of the double junction solar cell may be arranged in an arrangement on the base solar cell 120, the unit body 110 and the base solar cell 120 of the double junction solar cell are bonded to each other by wafer bonding. Can be. That is, the lower portion of the double junction solar cell unit 110 and the upper portion of the base solar cell 120 may be formed of a material that can be bonded to each other by wafer bonding. Here, wafer bonding is a technique of bonding different substrates by applying heat and pressure without using an adhesive.

3 and 4 are conceptual views showing a modification of the multi-junction solar cell of the present invention.

Referring to FIG. 3, the surface of the base solar cell 220 of the multi-junction solar cell 200 may have a predetermined shape. In detail, the surface of the base solar cell 220 exposed between the array of the double junction solar cell unit 210 may be etched to have a larger area than the plane. Thus, since the light receiving surface of the base solar cell 220 is wider, more current may be generated to increase the efficiency of the solar cell.

In addition, the predetermined shape may be formed into a pyramid shape, an inverted pyramid shape, a shape formed by a V-shaped groove, a shape formed concave in a semicircle, a shape formed convex in a semicircle, or a combination thereof. The above enumeration regarding the predetermined shape is merely illustrative, and if the area of the surface of the base solar cell 220 exposed between the array of the double junction solar cell unit 210 is formed to have a larger area than the plane, It is not limited.

Meanwhile, referring to FIG. 4, the multi-junction solar cell 300 may further include a glass layer 340 including a condenser lens 341 corresponding to the arrangement of the double junction solar cell unit 310.

In one embodiment, the condenser lens 341 is formed to condense sunlight to produce electricity, so that the condensing lens 341 of the multi-junction solar cell 300 includes a light transmitting layer 340 having the condenser lens 341. The light conversion efficiency can be increased.

The condenser lens 341 may be formed in a convex form toward the double junction solar cell unit 310 to condense sunlight. In addition, in order to reduce the thickness of the light transmitting layer 340 may be formed of a Fresnel lens (fresnel lesns) having a plurality of circle bands. Further, the condenser lenses 341 may be integrated with the light transmitting layer 340 of the same material. However, the present invention is not necessarily limited thereto, and the condenser lenses 341 may be separate lens-shaped members attached to the lower surface of the light transmitting layer 340.

Meanwhile, the light transmitting layer 340 may be formed of a light transmitting material such as glass, PC (polycarbonate), PMMA (Poly Methyl Meta Acrylate), or silicone. In addition, it may be a low iron tempered glass containing less iron in order to prevent the reflection of sunlight and to increase the transmittance of sunlight. However, the present invention is not limited thereto.

5 is a conceptual diagram illustrating a manufacturing method of the multi-junction solar cell 100 of the present invention. In the method of manufacturing the multi-junction solar cell 100 described below, the same or similar reference numerals are assigned to the same or similar components as the foregoing embodiments, and the description is replaced for the first time.

Referring to FIG. 5, the base solar cell 120 may be prepared, and the multi-junction solar cell 100 may be manufactured according to steps (a) to (h) of FIG. 5. The base solar cell 120 may be formed to absorb electricity of 650 to 1180 nm wavelength to produce electricity.

First, in the preparing of the base solar cell 120, the base solar cell 120 may be a silicon solar cell formed of a semiconductor including silicon. In addition, the base solar cell 120 may be formed of a Si / SiGe double junction solar cell. On the other hand, the upper portion of the base solar cell 120 is provided with a tunnel barrier, it may be connected in series with the double junction solar cell unit 110 to be described later. The tunnel barrier may be referred to as a second tunnel barrier to distinguish it from a first tunnel barrier (not shown) provided in a double junction solar cell unit to be described later.

In FIG. 5A, the sacrificial layer 150, the first solar cell layer 111 ′, the first tunnel barrier (not shown), and the second solar cell layer 112 ′ are formed on the growth substrate W. Referring to FIG. By sequentially growing, the double junction solar cell layer 10 including the III-V compound semiconductor may be formed.

Specifically, the growth substrate W may be a substrate having a constant surface, such as a sapphire substrate, a silicon substrate, and a GaAs substrate. In one embodiment, the sacrificial layer 150 may be formed of a layer that can be etched in a specific etching solution, preferably formed of an AlAs layer.

The first solar cell layer 111 ′ stacked on the sacrificial layer 150 may be formed of an AlGaAs compound semiconductor excluding indium (In). The first solar cell layer 111 ′ includes a first conductive semiconductor layer and a second conductive semiconductor layer formed of an AlGaAs compound semiconductor, which are bonded to each other to form a PN junction to generate electricity with sunlight. Can be. In particular, the first solar cell layer 111 ′ may generate electricity by absorbing sunlight having a wavelength of 300 to 670 nm.

Meanwhile, the second solar cell layer 112 ′ may be formed of a GaAs compound semiconductor. The first solar cell layer 111 ′ includes a first conductive semiconductor layer and a second conductive semiconductor layer on which a GaAs compound semiconductor is formed, which may be formed to be bonded to each other to form a PN junction to generate electricity with sunlight. have. The second solar cell layer 112 ′ may generate electricity by absorbing sunlight having a wavelength of 500 to 890 nm.

That is, in the step of forming the double junction solar cell layer 10, the material having a large band gap is sequentially stacked or grown. In detail, the sacrificial layer 150, the first solar cell layer 111 ′, and the second solar cell layer 112 ′ are formed in a band gap in order.

In addition, the first solar cell layer 111 ′ and the second solar cell layer are formed by a first tunnel barrier (not shown) disposed between the first solar cell layer 111 ′ and the second solar cell layer 112 ′. 112 'may be connected in series with each other.

In step (b) of FIG. 5, the step of forming the double junction solar cell layer 10 may be repeated a plurality of times to form a multilayer double junction solar cell layer 10 ′. It may be formed by a metal-organic chemical vapor deposition (MOCVD) process. In particular, step (b) of FIG. 5 forms the double junction solar cell layer 10 and is continuously performed in the MOCVD equipment.

That is, by forming a multi-layered double junction solar cell layer 10 ′, a process of increasing the temperature, growing the film, and lowering the temperature after the growth of the film can be eliminated when forming the single-layer double junction solar cell layer. Thus, the method of manufacturing a multi-junction solar cell comprising the step of forming the multi-junction solar cell layer 10 ′ by repeating the step of forming the double junction solar cell layer 10 a plurality of times is required during the process. This can reduce the growth time and cost of the membrane.

In step (c) of FIG. 5, the photoresist 160 is applied according to a known photolithography technique.

In step (d) of FIG. 5, the hardening region 160a and the uncured region 160b are formed by performing an exposure process on the mask 170 having the opening 171, and the uncured region according to a known photolithography technique. 160b is cleaned and removed.

In the step (e) of FIG. The battery unit 110 and the arrangement of the units are formed. As a result, a multi-junction solar cell layer body 10a having a double junction solar cell unit 110 and an array of units is formed.

In an embodiment, the first etching solution of step (e) of FIG. 5 may include selective etching, including citric acid. In detail, the first solar cell layer 111 ′, the first tunnel barrier layer (not shown), and the first double junction solar cell layer positioned on the top of the multilayer double junction solar cell layer 10 ′ as the first etching solution. The two solar cell layers 112 'are etched to form a double junction solar cell unit 110 and an array of units, and the sacrificial layer 150 is subjected to selective etching.

Thereafter, the curing region 160a provided on the upper portion of the double junction solar cell unit 110 is removed to proceed to the subsequent process.

In step (f) of FIG. 5, the double junction solar cell unit 110 and the array of units are bonded to the base solar cell 120 by wafer bonding. Wafer bonding is a technique of bonding different substrates by applying heat and pressure without using an adhesive.

In the step (g) of FIG. 5, the sacrificial layer is etched adjacent to the second solar cell of the double junction solar cell layer positioned at the top with the second etching solution, and the sacrificial layer is etched to double-junction solar cell unit 100 and The array of units may be separated from the multilayer double junction solar cell 10 ". In detail, the second solar cell of the double junction solar cell layer positioned on the uppermost portion by penetration of the second etching solution into the space between the array of units. Etching of the sacrificial layer adjacent to can be easily accomplished.

In an embodiment, the second etching solution may include hydrofluoric acid (HF) to etch the sacrificial layer 150 formed of the AlAs layer. Preferably, the second etching solution may be formed of a mixture of hydrofluoric acid and acetone, more preferably, hydrofluoric acid and acetone may be mixed in a volume ratio of 1: 1 to be used as the second etching solution.

In detail, the etching of the sacrificial layer 150 may be performed. The AlGaAs layer forming the first solar cell 111 may also be etched by hydrofluoric acid. However, since the AlGaAs layer forming the first solar cell 111 has an etching rate of one hundredth of that of the sacrificial layer 150 formed of the AlAs layer, the first solar cell 111 is formed while the sacrificial layer is etched. Since the AlGaAs layer forming is hardly etched, it does not affect the structure of the multi-junction solar cell 100.

In addition, the sacrificial layer disposed below the sacrificial layer adjacent to the second solar cell of the double junction solar cell layer disposed on the uppermost portion is exposed to only the outer side thereof, so that the sacrificial layer is not easily etched by the second etching solution.

Thus, in step (h) of FIG. 5, the multi-junction solar cell 100 of the present invention may be manufactured.

Furthermore, repeating the steps of (c) to (g) of FIG. 5 a plurality of times, the multi-junction solar cell 100 by successively bonding the double junction solar cell unit 100 to the base solar cell 120. It can manufacture. That is, a plurality of multi-junction solar cells 100 may be manufactured by repeating the step of etching the sacrificial layer 150 a plurality of times by applying the photoresist 160 to form the double-junction solar cell units 100. .

Thus, by repeating the steps of forming a double-junction solar cell unit of each layer of the double-junction solar cell layer formed on one growth substrate to etching the sacrificial layer to manufacture a multi-junction solar cell, it is coupled to the base solar cell Therefore, there is an effect of reducing the growth substrate cost consumed in producing multi-junction solar cells.

6 is a conceptual diagram showing a modification of the manufacturing method of the multi-junction solar cell 100 of the present invention.

Referring to FIG. 6, a plurality of double-junction solar cell units 110 and a multi-layer double-junction solar cell layer body 10a in which an array of units are formed are bonded to a base solar cell 120 ′ formed with a large area by wafer bonding. Next, the sacrificial layer 150 is etched to form a multi-junction solar cell 100 ′. Subsequently, a large area of the base solar cell 120 'may be cut to form a plurality of multi-junction solar cells 100 in one process.

In addition, the method may further include etching the surface of the base solar cell 120 between the array of the double junction solar cell units 110 after etching the sacrificial layer 150, to the surface of the base solar cell 120. It is also possible to form a predetermined shape. In addition, the method may further include stacking a light transmitting layer including a light collecting lens corresponding to the arrangement of the double junction solar cell unit 110, to manufacture a multijunction solar cell.

The multi-junction solar cell described above is not limited to the configuration and method of the embodiments described above, but the embodiments may be configured by selectively combining all or part of the embodiments so that various modifications can be made. .

100, 200, 300: multi-junction solar cell
110, 210, 310: double junction solar cell unit
111, 211, and 311: first solar cell
112, 212, and 312: second solar cell
113, 213, 313: Tunnel 1
120, 220, 320: base solar cell
130, 230, 330: Tunnel 2 barrier
340: light transmitting layer
150: sacrificial layer
160: photoresist

Claims (18)

A double junction solar cell unit comprising a III-V compound semiconductor; And
A base solar cell formed of a semiconductor including silicon disposed under the array of the double junction solar cell units,
The lower portion of the double junction solar cell unit and the upper portion of the base solar cell are formed of a material that can be bonded to each other by wafer bonding,
On the base solar cell, a plurality of double junction solar cell units form a constant array,
The double junction solar cell unit,
A first solar cell;
A first solar cell and a second solar cell disposed below; And
And a first tunnel barrier disposed between the first solar cell and the second solar cell. The method of claim 1,
The first solar cell of the double junction solar cell unit is a multi-junction solar cell, characterized in that formed of AlGaAs compound semiconductor. The method of claim 1,
The second solar cell of the double junction solar cell unit is a multi-junction solar cell, characterized in that formed of a GaAs compound semiconductor. The method of claim 1,
And a second tunnel barrier between the double junction solar cell unit and the base solar cell. The method of claim 1,
The surface of the base solar cell exposed between the array of the double junction solar cell unit is a multi-junction solar cell, characterized in that it has a predetermined shape. The method of claim 1,
The base solar cell is a multi-junction solar cell, characterized in that formed of a silicon solar cell. The method of claim 1,
The base solar cell is a multi-junction solar cell, characterized in that formed of Si / SiGe double junction solar cell. The method of claim 1,
And a light transmitting layer having a condensing lens corresponding to the arrangement of the double junction solar cell unit. In the manufacturing method of a multi-junction solar cell,
Preparing a base solar cell;
Sequentially growing a sacrificial layer, a first solar cell layer, a first tunnel barrier layer, and a second solar cell layer on the growth substrate to form a double junction solar cell layer including a III-V compound semiconductor;
Repeating the step of forming the double junction solar cell layer a plurality of times to form a multilayer double junction solar cell layer;
Etching the double-junction solar cell layer positioned on the top of the multilayer double-junction solar cell layer with a first etching solution in a predetermined pattern to form an array of double-junction solar cell units and units;
Coupling the double junction solar cell unit and the array of units to a base solar cell by wafer bonding; And
Etching the sacrificial layer adjacent to the second solar cell of the double junction solar cell layer positioned on the top with the second etching solution;
In the etching of the sacrificial layer, the double junction solar cell unit and the array of units are separated from the multilayer double junction solar cell,
And forming the sacrificial layer by etching the double junction solar cell unit and the array of units a plurality of times. The method of claim 9,
The method of manufacturing a multi-junction solar cell, wherein the base solar cell is formed of a silicon solar cell in the step of preparing the base solar cell. The method of claim 9,
The method of manufacturing a multi-junction solar cell, wherein the base solar cell is formed of a Si / SiGe double junction solar cell in the step of preparing the base solar cell. The method of claim 9,
The method of manufacturing a multi-junction solar cell, characterized in that further comprising the step of forming a second tunnel barrier on top of the base solar cell in preparing the base solar cell. The method of claim 9,
In the step of forming the double junction solar cell layer, the sacrificial layer is a method of manufacturing a multi-junction solar cell, characterized in that formed of an AlAs layer. The method of claim 9,
In the step of forming the double junction solar cell layer, the first solar cell layer is a manufacturing method of a multi-junction solar cell, characterized in that formed of AlGaAs compound semiconductor. The method of claim 9,
In the step of forming the double junction solar cell layer, the second solar cell layer is a manufacturing method of a multi-junction solar cell, characterized in that formed of a GaAs compound semiconductor. The method of claim 9,
In the forming of the double junction solar cell unit and the array of units, the first etching solution is a multi-junction solar cell, characterized in that for etching the first solar cell layer, the first tunnel barrier layer and the second solar cell layer. Manufacturing method. The method of claim 9,
And etching the surface of the base solar cell between the array of the double-junction solar cell units after the etching of the sacrificial layer. The method of claim 9,
The method of manufacturing a multi-junction solar cell, characterized in that it further comprises the step of laminating a light transmitting layer having a condensing lens corresponding to the arrangement of the double-junction solar cell unit.

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