KR101455723B1 - High efficiency Nanorod solar cell using reusing Si substrate and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a high efficiency III-V nanorod solar cell reusing a silicon substrate and a manufacturing method thereof. An optical device including the high efficiency solar cell is obtained without using an expensive compound semiconductor substrate by growing a high efficiency stacked III-V and Ge nanorod solar cell structure on the silicon substrate, separating the grown stacked nanorod solar cell from the silicon substrate, and continuously using the silicon substrate which is used in a solar cell epitaxial structure growth. A III-V group compound with a lattice constant which is matched is grown on the surface of the silicon substrate as a buffer layer. A III-V material layer including high density Al which is easily etched by HF solutions is grown on the surface thereof as a sacrificial layer. A high efficiency III-V group epitaxial structure combining a III-V compound material and a Ge material is formed on the surface thereof with a stack type. The solar cell epitaxial structure is easily separated from the silicon substrate through the sacrificial layer by a BLO method of a transfer and strain induced method. The substrate is continuously used unlike a GaAs substrate by completely and selectively etching the remaining III-V layers on the silicon substrate after ELO. Thereby, the high efficiency solar cell and the optical device are formed by continuously reusing a cheap substrate like Si without using an expensive substrate.

Description

TECHNICAL FIELD [0001] The present invention relates to a high efficiency III-V nanorod solar cell recycling a silicon substrate and a manufacturing method thereof,

This invention grown by, particularly, III-V GaP buffer layer of the surface of the silicon (Si) substrate according to a high-efficiency III-V nanorods (Nanorod) solar cell and a method of producing the recycled silicon substrate, and Al _{0. 9} Ga _{0 .1} P SL layer is grown and then the solar cell structure is grown to form a multi-junction nanorod solar cell having a double junction or higher. As the SL layer is selectively etched in the HF solution, a solar cell structure V nanodevice solar cell which recycles a silicon substrate which is separated and recycled by continuously etching the GaP buffer layer to recycle the silicon (Si) substrate.

After the adoption of the Kyoto Protocol in December 1997 to regulate carbon dioxide emissions, the main contributor to global warming, research on renewable and clean alternative energy sources such as solar, wind, and hydro It is actively proceeding.

Photovoltaic devices (solar cells), which are attracting attention as clean alternative energy, are devices that generate current-voltage by utilizing the photovoltaic effect in which semiconductor absorbs light and electrons and holes are generated.

Although np diodes of inorganic semiconductors such as silicon or gallium arsenide (GaAs), which have proven to be stable and efficient as semiconductors for photovoltaic devices, have been mainly used, they have been a stumbling block to the practical use of solar cells due to their high manufacturing costs.

In order to develop cheaper photovoltaic devices, researches on photovoltaic devices using dye sensitive materials and organic / polymer materials are being actively carried out, but the efficiency is very low compared with silicon based photovoltaic devices and the lifetime due to deterioration is short, The ratio is only about 3%.

As described above, the majority of photovoltaic devices use silicon single crystals or silicon polycrystals. However, the cost of silicon materials and wafers in solar photovoltaic systems is more than 40% of the total construction cost. As a practical solution, efforts are being made to reduce the amount of silicon needed for unit power production through morphology / eg engineering approaches and to minimize silicon consumption with thin film devices.

Conventional technologies for fabricating III-V solar cells and optoelectronic devices on the surface of a silicon substrate are mainly composed of a GaAs single junction or a GaAs / InGaAs or AlGaAs / GaAs double junction epitaxial growth on one side with a silicon substrate as a medium. The same III-V compound semiconductors can be applied not only to electronic devices such as diode transistors, but also to photoelectric devices such as laser diodes, photodiodes or solar cells.

In order to use such a compound semiconductor, a Group VI substrate is generally used. However, since materials having a VI group substrate and a III-V group compound semiconductor have a fundamental physical property difference such as a crystal structure, a lattice constant, or a thermal expansion coefficient, defects are generated therein and the uniformity of the surface is poor .

Therefore, in order to solve such a problem, a method of inserting a buffer layer capable of reducing the lattice constant difference between the substrate and the compound semiconductor layer or a method of growing into a superlattice layer such as InGaAs / GaAs and GaAsP / GaAs has been proposed .

However, the method of manufacturing a semiconductor as described above causes problems such as an increase in the thickness of the semiconductor layer and an increase in manufacturing cost, and at the same time, there is no way to recycle the substrate.

Thus, recycling of III-V substrates has been reported as a low-cost method for high-efficiency III-V solar cells and photoelectric devices [1].

¹ Ref. nature 465, 329 (2010)

According to the above document, when the substrate is recycled about 3 times, there is a problem that the performance is maintained to be 85% in comparison with the existing performance, and the performance is rapidly deteriorated when recycled more than 3 times.

The reason for the rapid decrease of the performance is that the selective etching after the epitaxial lift-off (ELO) with the substrate is not properly performed for the Al _{0 .9} Ga _{0 .1} As and GaAs buffer layers of the sacrificial layer (SL) The surface roughness of the remaining materials causes deterioration of performance.

Further, there was no method of recycling the silicon (Si) substrate after removing the nanorod III-V from the silicon (Si) substrate.

Methods for removing the photovoltaic epilayer from a GaAs-based substrate include a method of removing using a strain and an etching solution, and a method of removing the photovoltaic layer using a transfer and a magnetic field by etching.

The structure of the solar cell on the surface of the sacrificial layer (SL) can be variously shaped according to the growth method and the ELO (epitaxial lift-off) method.

Although the kinds of epi to be grown by the method of growing a GaP buffer layer on the surface of a silicon (Si) substrate are various, an anti phase domain (APD) defect between the hetero atoms growing on a single element surface such as a silicon (Si) There is a constant deficiency.

In recent years, a disadvantage due to the difference in lattice constants has been proposed, which can overcome the disadvantages of growth direction by using one-dimensional nanowire growth. Accordingly, development of nanowire growth using MOCVD or MBE has been actively developed.

As a method for growing a 1-D nanowire having a one-dimensional growth direction, a VLS method (JE Allen, ER Hemesath, DE Perea, JL Lensch-Falk, LiZ.Y. Yin, MH Gass, P. Wang, AL Bleloch, RE Palmer, and LJ Lauhon, "High-resolution detection of Au catalysts in Si nanowires," Nat Nano, vol. 3, pp. 168-173, 2008], SiO ₂ using e-beam lithography How to grow nanowires on a pattern surface [K. Tomioka, "Control of InAs nanowire growth directions on Si," Nano Letters, vol. 8, pp. 3475-3480, 2008), and a Volmer-Weber nanowire growth method using a strain resulting from a difference in gap from a silicon substrate without any catalyst or pattern (SA Fortuna, JG Wen, IS Chun, Planar GaAs Nanowires on GaAs Substrates: Self-Aligned, Nearly Twin-Defect Free, and Transfer-Printable, "Nano Letters, vol. 8, pp. 4421-4427, 2008].

However, according to the conventional method for growing 1-D nanowires, a method of growing a single junction or a double junction on the surface thereof by using a Si or GaAs substrate is proposed. There was no way to recycle the silicon substrate.

This invention grown conventional intended to solve the problem, growing a GaP buffer layer of III-V on a surface of a silicon (Si) substrate, and Al _{0 .9} Ga _{0 .1} P SL layer as described above, and then, the sun The present invention provides a highly efficient III-V nanorod solar cell in which a silicon substrate having a double-junction or more multi-junction nanorod solar cell is grown by growing the cell structure, and a method of manufacturing the same.

Another object of the present invention is to isolate the solar cell structure on the surface of the SL layer selectively etched in the HF solution and cleanly etch the GaP buffer layer so that the silicon (Si) substrate can be recycled and used continuously .

In order to accomplish the above object, a high efficiency III-V nanodevice solar cell recycling a silicon substrate according to the present invention comprises:

We have made it possible to grow highly efficient stacked III-V and Ge Nanorod solar cell structures on a silicon substrate, make the grown stacked-type Nanorod solar cells isolate from the silicon substrate, So that an optical device including a highly efficient solar cell can be obtained without using an expensive compound semiconductor substrate.

Further, a III-V compound having a lattice constant coinciding with the surface of the silicon substrate is grown as a buffer layer, and a III-V material layer containing a high concentration of Al, which is easily etched in the HF solution, is grown on the surface thereof as a sacrificial layer, And a high-efficiency III-V epilayer structure in which the III-V compound material and the Ge material are bonded to the surface is formed in a laminated form.

In addition, the photovoltaic epitaxial structure can be easily removed from the silicon substrate through the sacrificial layer by the transfer and strain induced method BLO (epitaxial lift-off) method, and the III-V layers remaining after the ELO in the silicon substrate are selectively Unlike the GaAs substrate, the substrate can be continuously used, making it possible to consistently recycle low-cost substrates such as Si without using an expensive substrate to constitute a high-efficiency solar cell and an optical device. do.

The high-efficiency III-V nanorod solar cell recycled from the silicon substrate according to the present invention can be obtained by using a silicon (Si) substrate to obtain a high-efficiency nano solar cell without using any expensive substrate such as GaAs , The solar cell epitaxial layer is separated and applied to a flexible solar cell. The remaining silicon substrate is etched with a selective etching solution, and then a clean silicon substrate is continuously used for recycling while being used. However, in the present invention, a method of growing a nano-rod by applying a single or double junction III-V compound only to a III-V compound nano solar cell, Gt; to < RTI ID = 0.0 > InAs, Ge < / RTI > There is an effect.

FIGS. 1A and 1B are schematic views showing the structure of a flexible high-efficiency nanorod solar cell using the recycled silicon substrate of the present invention. FIG.
FIGS. 2A and 2B are schematic diagrams showing the construction of a nanorod solar cell for reusing a silicon substrate of the present invention. FIG.
FIG. 3 is a diagram showing energy bandgaps and lattice constants of nanorods to be grown on the surface of a silicon substrate of the present invention, and an energy distribution corresponding to materials in the solar spectrum.
4 is a schematic view showing the configuration of a nanorod solar cell semiconductor to be grown on the surface of a silicon substrate of the present invention.
5 is a schematic view showing a flexible process of a high-efficiency nanorod solar cell to be grown on the surface of a silicon substrate of the present invention.
6 is a schematic view showing a flexible process of a high efficiency nanorod solar cell grown on the surface of a silicon substrate of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1A schematically shows the structure of a high efficiency III-V nanorod solar cell using a recycled silicon substrate having a high energy band gap structure on the growth surface of the present invention. A buffer layer 2 of a GaAs layer or a GaP layer having a lattice constant different by 4% or more is grown and a sacrificial layer (SL) 3 containing high-concentration Al is formed on the buffer layer 2, V nanorod solar cell 5 is formed on top of the flexible substrate 4 and the stacked high efficiency III-V nanorod solar cell 5 is formed on the flexible substrate 4, And a conductive metal layer 6 is formed on a part of the upper surface of the substrate 1.

In order to reuse the silicon (Si) substrate 1, the sacrificial layer (SL) 3 containing Al is removed by etching.

The stacked high efficiency III-V nanodevice solar cell 5 may have various forms depending on the growth method and ELO (epitaxy lift-off).

FIG. 1B schematically shows the structure of a high-efficiency III-V nanodevice solar cell using a recycled silicon substrate having a low energy band gap in the upper layer of the growth surface of the present invention. V multilayer solar cell 13 is formed on the surface of the conductive metal layer 12 and a part of the upper surface of the stacked high-efficiency III-V nanodevice solar cell 13 is covered with a metal layer 12, A buffer layer 16 of a GaAs layer or a GaP layer having a lattice constant of less than 0.5% is grown under the silicon (Si) substrate 15, And a sacrificial layer (SL) 17 containing high-concentration Al is formed on the upper surface of the stacked high-efficiency III-V nanodevice solar cell 13, and a sacrificial layer (SL)

In order to reuse the silicon (Si) substrate 1, the sacrificial layer (SL) 17 including Al is etched and removed.

A process of cleaning the surface of the silicon (Si) substrate is as follows.

The silicon (Si) substrate is first etched by hydrofluoric acid (HF) for 1 minute and the etched silicon (Si) substrate is cleaned with Piranha by a solution of H ₂ SO ₄ and H ₂ O ₂ in a ratio of 3: 1 Etching the silicon (Si) substrate for 20 minutes by a BOE (Buffered Oxide Etchant) method, and rinsing the silicon (Si) substrate for 7 seconds by DI (deionized) A step of evaporating water while drying the cleaned silicon substrate with an N ₂ Gun and a step of rapidly introducing the evaporated silicon substrate into a metalorganic chemical vapor deposition (MOCVD) reaction tube to remove the GaAs layer And then performing the deposition process.

The silicon (Si) when the pattern in the SiO ₂ on the substrate is then etched with BOE, washed, and the SiO ₂ etching in a short time on the surface of the deposited the dried immediately SiO ₂ to N ₂ Gun and opened to 7 seconds DI So that the pattern is formed.

And when using the Au catalyst, the leave after washing processed in the manner of, and washed for 7 seconds and then immersed for 2 minutes in Poly-L-lysine sown in the following, syringe using the Au nano particle, 30sec N ₂ Blow dry with a gun.

2A schematically shows the structure of a nanorod solar cell for reusing a silicon substrate having a structure having a high energy band gap in an upper layer of the growth surface according to the present invention. The silicon substrate 21 has a lattice mismatch A GaP buffer layer 22 having a thickness of 0.5% or less is grown to grow a sacrificial layer (SL) 23 of high concentration Al _{0 .9} Ga _{0 .1} P on the surface of the buffer layer 22, 23, the nanoderm cell 24 is formed on the surface.

The nanodevice solar cell 24 is formed by growing a buffer layer 25 of GaP on the surface of the nanodevice solar cell 24 in contact with the sacrificial layer 23 and forming an organic substance such as benzocyclobutene (BCB) a ZnO layer 28 of a semiconductor material is grown on the surface of the BCB layer 26 and a highly efficient multilayer structure III is formed on the BCB layer 26 and the ZnO layer 28. [ -V and Ge nanorods 27 and 29, respectively, and the conductive metal layer 30 is formed on the surface of the buffer layer 25 and the ZnO layer 28 of the GaP.

In order to reuse the nanodevice solar cell, a sacrificial layer (SL) 23 of Al _{0 .9} Ga _{0 .1} P is etched and removed.

Here, the reason why the lattice mismatch is to grow the GaP buffer layer 22 of 0.5% or less of the silicon substrate 21 is to grow the buffer layer of good quality so that the Al _{0 .9} Ga _{0 .1} P layer And the nanorods 27 and 29 can be grown.

Si and GaP do not have much difference in lattice constant, but they can grow with defects due to APD (Anti Phase Domain) due to the need to grow heterogeneous elements on the surface of homologous elements.

Therefore, in order to reduce the APD, a method such as TCA (Thermal Cycling Annealing), which is a process of growing at a high temperature and changing a periodic temperature, is used.

2B schematically shows the structure of a nanodevice solar cell for reusing a silicon substrate having a low energy bandgap in the upper layer of the growth surface of the present invention. The silicon substrate (31) has a lattice mismatch GaP buffer layer 32 having a thickness of 0.5% or less is grown to grow a sacrificial layer (SL) 33 of high concentration Al _{0 .9} Ga _{0 .1} P on the surface of the buffer layer 32, 33 are formed on the surface of the nanorod solar cell 34 in contact with the nanorods.

The nanorod solar cell 34 is formed by growing a buffer layer 35 of GaP on the surface of the nanorod solar cell 34 in contact with the sacrificial layer 33 and forming an organic benzocyclobutene (BCB) layer on part of the surface of the buffer layer 35 of GaP. a ZnO layer 38 of a semiconductor material is grown on the surface of the BCB layer 36 and a highly efficient multilayer structure III is formed on the BCB layer 36 and the ZnO layer 38. [ -V and Ge nanorods 37 and 39, respectively, and the conductive metal layer 40 is formed on the surface of the ZnO layer 38.

And it should be removed by etching the sacrificial layer (SL) (33) in order to re-use the nanorods solar cell of the Al _{0 .9} Ga _{0 .1} P.

FIG. 3 shows the energy band gap and the corresponding range of the solar spectrum of the multi-junction high efficiency solar cell structure recycled to the substrate.

4A shows a structure of a nanorod solar cell semiconductor grown on the surface of a silicon substrate having a high energy band gap structure on the growth surface of the present invention. The GaN buffer layer and the Al _{0 .9} Ga _{0 .1} (P, n) -Ge (Eg = 100 nm) on the surface of the silicon (Si) substrate. The stacked nanorods for the high efficiency III- The first semiconductor layer 51 is grown vertically so that the surface of the first semiconductor layer 51 is made of InAlP, InGaP, GaAs , The first tunneling structure 52 of the Ge junction is vertically grown.

A second semiconductor layer 53 of (p, n) -GaAs (Eg = 1.4 eV) is vertically grown on the surface of the first tunneling structure 52, A second tunneling structure 54 of InAlP, InGaP, GaAs, and Ge junctions is vertically grown on the surface of the second tunneling structure 54, and (p, n) -InGaAlP (Eg = 1.8 - And the third tunneling structure 56 of InAlP, InGaP, GaAs, and Ge junction is vertically extended on the surface of the third semiconductor layer 55. The third semiconductor layer 55 is grown vertically A fourth semiconductor layer 57 of AlGaP (Eg = 2.26 to 2.34 eV) is vertically grown on the surface of the third tunneling structure 56 and grown on the surface of the fourth semiconductor layer 57 The window layer 58 is formed so as to form a single junction, a double junction, a triple junction, and a multiple junction.

Through the thin tunneling structures 52, 54, and 56 of the first to third high concentrations.

In addition, nanorod solar cell semiconductors are manufactured while omitting the specific semiconductor layers 51, 53, 55, and 57 as occasion demands.

FIG. 4B shows a structure of a nanorod solar cell semiconductor grown on the surface of a silicon substrate having a low energy band gap structure of the growth surface of the present invention. The GaN buffer layer and the Al _{0 .9} Ga _{0 .1} Layer laminate for a high-efficiency III-V nanorod solar cell is formed by growing AlGaP (Eg = 2.26 to 2.34 eV) on the surface of a silicon (Si) substrate, The first semiconductor layer 61 is vertically grown.

A first tunneling structure 62 of InAlP, InGaP, GaAs, and Ge junctions is vertically grown on the surface of the first semiconductor layer 61, and p and n (n) are formed on the surface of the first tunneling structure 62, ) -InGaAlP (Eg = 1.8 to 1.94 eV) is grown vertically and the second semiconductor layer 63 is grown on the surface of the second semiconductor layer 63 by a second tunneling of InAlP, InGaP, GaAs, The structure 64 is grown vertically and a third semiconductor layer 65 of (p, n) -GaAs (Eg = 1.4 eV) is vertically grown on the surface of the second tunneling structure 64 , A third tunneling structure 66 of InAlP, InGaP, GaAs, and Ge junctions is vertically grown on the surface of the third semiconductor layer 65, and p (p) is grown on the surface of the third tunneling structure 66 (n) -Ge or (p, n) -InGaAs (Eg = 0.3-1.4 eV) is vertically grown and the surface of the fourth semiconductor layer 67 is covered with a window layer 68) to form a single junction, a double junction, a triple junction, and a multiple junction .

In the process of forming the solar cell, a GaP buffer layer and an Al _{0 .9} Ga _{0 .1} P sacrificial layer (SL) are grown on a silicon substrate, and a solar cell structure is grown on the surface. Coating the surface of the layer with BCB at 5000 rpm, performing a heat treatment process at 300 ° C for 2 hours on the BCB-coated silicon substrate, and then subjecting it to a reactive ion etching (RIE) And etched at an appropriate height using CF ₄ gas.

And a transparent electrode is deposited on the etched surface at a temperature of 380 to 400 ° C.

A process for recycling a substrate while removing an epi layer from a silicon (Si) substrate or fabricating it as a flexible photoelectric device is as follows.

As shown in FIG. 5, the ELO (epitaxial lift-off) method according to the transfer method for removing the epilayer of the solar cell grown up to the normal after the growth of the solar cell structure includes the steps of preparing a wafer for transfer A step of attaching and detaching a solar cell from a substrate while attaching the solar cell to a stamp, a step of moving a stamp including the desorbed solar cell to a carrier substrate, And a step of attaching a stamp including a battery to a carrier substrate.

As shown in FIG. 6, the method of removing the epi layer using hydrofluoric acid (HF) is as follows. After spinning at 4000 rpm for 30 seconds and then baking for 2 minutes at 100 ° C, A process of printing an ELO (epitaxial lift-off) hole capable of adjusting the size and spacing of holes, a process of transferring PDMS (polydimethylsiloxane) in which holes are printed to another substrate, a sacrificial layer (HF) is injected into the holes formed up to the sacrificial layer, and the process is performed by a process of grabbing and removing the HF by the magnetic force to the structure of the injected solar cell. do.

The ELO (epitaxial lift-off) method by the strain induced method which removes the epilayer of the solar cell grown in reverse phase after the solar cell structure growth is performed between the substrate and the epilayer to be peeled off as shown in FIG. , The epitaxial layer is selectively wound around a rotating cylinder for moving the magnetic body so as to separate the epi layer.

Then, as shown in Fig. 8, the substrate is held on the support bar while the flexible carrier is pulled by the heavy material so as to be separated by the release layer.

On the other hand, in order to remove the remaining GaAs or GaP after separating the epi layer by the ELO (epitaxial lift-off) method in the above-mentioned silicon (Si) substrate, H ₂ SO ₄ , H ₂ O ₂ , H ₂ O and H ₃ PO _4, by using an etching solution (wet etchant), such as HCl and to perform selectively etched with respect to silicon (Si) substrate.

Therefore, it is possible to cleanly etch the remaining III-V materials on the surface of the silicon (Si) substrate with this etching solution, and the structure of the solar cell can be grown on the silicon (Si) substrate again in a good surface environment so as to be reusable.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but many variations and modifications may be made without departing from the scope of the invention. It will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

1: p-Si substrate 2: GaAs layer or buffer layer of GaP layer
3: sacrificial layer (SL) including high concentration Al 4: flexible substrate
5: Laminated High Efficiency III-V Solar Cell 6: Conductive Metal Layer

Claims (10)

The silicon substrate 1 is etched by hydrofluoric acid (HF) for 1 minute and then washed with Piranha in a solution of H ₂ SO ₄ and H ₂ O ₂ mixed at a ratio of 3: 1. The silicon substrate 1 thus cleaned is subjected to oxide etching (BOE: Buffered Oxide Etchant) for 20 minutes, followed by Rinse treatment with DI (deionized) for 7 seconds, and the silicon substrate 1 was dried with N ₂ Gun to evaporate the water. Then, MOCVD (metalorganic chemical vapor deposition reaction tube to clean the surface of the silicon substrate 1;
Growing a buffer layer (2) of GaAs or GaP having a lattice constant discrepancy of 4% or more on the silicon substrate (1);
Growing a sacrificial layer (SL, 3) of AlGaAs or AlGaP formed on the buffer layer (2) with a certain concentration of Al;
Forming a flexible substrate (4) on the sacrificial layer (3);
Forming a III-V nanorod solar cell (5) structure on the flexible substrate (4);
Forming a conductive metal layer (6) on a part of the upper surface of the III-V nanodevice solar cell (5);
Etching the sacrificial layer (3) around the solar cell structure to separate the grown solar cell structure on the silicon substrate (1) through ELO (Epitaxial Lift-off); And
The GaAs or GaP remaining in the silicon substrate 1 may be etched by using at least one etching solution of wet etching such as H ₂ SO ₄ , H ₂ O ₂ , H ₂ O, H ₃ PO ₄ , and HCl so that the separated silicon substrate can be recycled. etchant. < / RTI > The method of manufacturing a high efficiency III-V nanorod solar cell recycled from a silicon substrate.
delete The silicon substrate was etched by hydrofluoric acid (HF) for 1 minute and then washed with Piranha in a mixed solution of H ₂ SO ₄ and H ₂ O ₂ in a ratio of 3: 1. The cleaned silicon substrate 1 was subjected to oxide etching (BOE: Buffered Oxide Etchant) for 20 minutes and then rinsed with DI (deionized) for 7 seconds. The silicon substrate 1 was dried with N ₂ Gun to evaporate the water and then subjected to metalorganic chemical vapor deposition (MOCVD) Cleaning the surface of the silicon substrate in a tube;
Growing a buffer layer of a GaAs layer or a GaP layer below the silicon substrate with a lattice constant mismatch of less than 0.5%;
Forming a sacrificial layer including a predetermined concentration of Al below the buffer layer;
Forming a conductive metal layer below the sacrificial layer;
Forming a III-V nanodevail solar cell structure on the surface of the conductive metal layer;
Forming a metal layer for conductivity on the bottom of the III-V nanodevice solar cell;
Forming a flexible substrate on the conductive metal layer;
Etching the sacrificial layer to remove the grown III-V nanorod solar cell structure through ELO (Epitaxial Lift-off) on the silicon substrate; And
In order to recycle the separated silicon substrate, GaAs or GaP remaining on the silicon substrate is etched with at least one wet etchant of H ₂ SO ₄ , H ₂ O ₂ , H ₂ O, H ₃ PO ₄ , and HCl The method comprising the steps of: (a) etching a silicon substrate to form a silicon substrate;
The silicon substrate was etched by hydrofluoric acid (HF) for 1 minute and then washed with Piranha in a mixed solution of H ₂ SO ₄ and H ₂ O ₂ in a ratio of 3: 1. The cleaned silicon substrate 1 was subjected to oxide etching (BOE: Buffered Oxide Etchant) for 20 minutes and then rinsed with DI (deionized) for 7 seconds. The silicon substrate 1 was dried with N ₂ Gun to evaporate the water and then subjected to metalorganic chemical vapor deposition (MOCVD) Cleaning the surface of the silicon substrate in a tube;
Growing a GaP buffer layer having a lattice constant mismatch of 0.5% or less on the surface of the silicon substrate;
Growing a sacrificial layer of Al _0.9 Ga _0.1 P on the surface of the buffer layer;
Growing a buffer layer of GaP on the surface in contact with the sacrificial layer;
Growing a BCB layer of benzocyclobutene (BCB), which is organic, on a surface of the GaP buffer layer;
Growing a ZnO layer of semiconductor material on the surface of the BCB layer;
Growing III-V and Ge nanorods in the BCB layer and the ZnO layer, respectively;
Forming a conductive metal layer on the surface of the GaP buffer layer and the ZnO layer;
Etching the sacrificial layer to isolate the grown nanorod structure from the silicon substrate through ELO (epitaxial lift-off); And
In order to recycle the separated silicon substrate, GaAs or GaP remaining on the silicon substrate is etched with at least one wet etchant of H ₂ SO ₄ , H ₂ O ₂ , H ₂ O, H ₃ PO ₄ , and HCl The method comprising the steps of: (a) etching a silicon substrate to form a silicon substrate;
The silicon substrate was etched by hydrofluoric acid (HF) for 1 minute and then washed with Piranha in a mixed solution of H ₂ SO ₄ and H ₂ O ₂ in a ratio of 3: 1. The cleaned silicon substrate 1 was subjected to oxide etching (BOE: Buffered Oxide Etchant) for 20 minutes and then rinsed with DI (deionized) for 7 seconds. The silicon substrate 1 was dried with N ₂ Gun to evaporate the water and then subjected to metalorganic chemical vapor deposition (MOCVD) Cleaning the surface of the silicon substrate in a tube;
Growing a GaP buffer layer having a lattice constant mismatch of 0.5% or less on the surface of the silicon substrate;
Growing a sacrificial layer of Al _0.9 Ga _0.1 P on the surface of the buffer layer;
Growing a buffer layer of GaP on the surface in contact with the sacrificial layer;
Growing a BCB layer of benzocyclobutene (BCB), which is organic, on a surface of the GaP buffer layer;
Growing a ZnO layer of semiconductor material on the surface of the BCB layer;
Growing III-V and Ge nanorods in the BCB layer and the ZnO layer, respectively;
Forming a conductive metal layer on the surface of the ZnO layer and etching the center electrode on the sacrificial layer; separating the grown nanorod structure on the silicon substrate through ELO (epitaxial lift-off); And
In order to recycle the separated silicon substrate, GaAs or GaP remaining on the silicon substrate is etched with at least one wet etchant of H ₂ SO ₄ , H ₂ O ₂ , H ₂ O, H ₃ PO ₄ , and HCl The method comprising the steps of: (a) etching a silicon substrate to form a silicon substrate; delete delete delete delete delete

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