TWI513012B - Solar cell with hetrojunction and a manufacturing method thereof - Google Patents

Description

Heterojunction solar cell and method of manufacturing same

The present invention relates to a heterojunction solar cell and a method of fabricating the same, and more particularly to a heterojunction in which a first amorphous germanium semiconductor layer is coated with a first extended cladding portion of a first patterned transparent conductive layer to increase photoelectric conversion efficiency. Surface solar cell and its manufacturing method.

Please refer to the first figure. The first figure shows a schematic cross-section of a prior art heterojunction twin solar cell. As shown, a heterojunction twinned solar cell PA100 includes a solar cell body PA1, a transparent conductive layer PA2, a first electrode PA3, and a second electrode PA4. The solar cell body PA1 includes a twinned semiconductor layer PA11, a first intrinsic amorphous germanium semiconductor layer PA12, a first amorphous germanium semiconductor layer PA13, a second intrinsic amorphous germanium semiconductor layer PA14, and a second amorphous germanium. Semiconductor layer PA15.

The first intrinsic amorphous germanium semiconductor layer PA12 and the second intrinsic amorphous germanium semiconductor layer PA14 are respectively formed on both sides of the twinned semiconductor layer PA11, and the first amorphous germanium semiconductor layer PA13 and the second amorphous germanium semiconductor layer PA15 Formed on the first intrinsic amorphous germanium semiconductor layer PA12 and the second intrinsic amorphous germanium semiconductor layer PA14, respectively, and finally the transparent conductive layer PA2 Further, it is entirely formed on the periphery of the first amorphous germanium semiconductor layer PA13 and the second amorphous germanium semiconductor layer PA15. The first electrode PA3 and the second electrode PA4 are respectively disposed on both sides of the transparent conductive layer PA2 for collecting current.

In order to avoid short circuit of the transparent conductive layer PA2 on the upper and lower sides, the transparent conductive layer PA2 is generally divided into two by laser cutting at the first insulating portion PA21 and the second insulating portion PA22 of the transparent conductive layer PA2. In part, the first electrode PA3 and the second electrode PA4 can collect carriers separately without generating leakage current.

Please refer to the second figure, which shows a schematic plan view of another heterojunction twin solar cell of the prior art. As shown in the figure, the structure of a heterojunction twinned solar cell PA200 is similar to that of the above-described heterojunction twin solar cell PA100, but in order to avoid leakage currents of the transparent conductive layers on the upper and lower sides due to contact at the side. When the transparent conductive layer PA2a on the upper and lower sides of the heterojunction twinned solar cell PA200 is formed, the mask is shielded directly, and the edge of the solar cell body PA1a of the heterojunction twinned solar cell PA200 is exposed without The transparent conductive layer PA2a is not covered by the edge of the solar cell body PA1a.

As described above, the conventional method can effectively prevent the upper and lower transparent conductive layers PA2a from contacting each other at the edges, but also loses the side absorbance, resulting in a decrease in photoelectric conversion efficiency, so how to avoid the side edges Increasing the overall light-receiving area while leaking current has been a problem to be solved in the field.

In view of the prior art, existing heterojunction solar cells are After the transparent conductive layer is formed, a two-part transparent conductive layer can be separated by a laser cutting process, but the cost in the process can be increased. However, although a transparent conductive layer can be formed, a mask can be used to avoid The edge of the solar cell body is covered by the transparent conductive layer, thereby preventing the transparent conductive layer from generating leakage current on the side, but this method loses the light absorption rate and reduces the photoelectric conversion efficiency of the solar cell.

Accordingly, the main object of the present invention is to provide a heterojunction solar cell and a method of fabricating the same, which not only does not need to separately separate two transparent conductive layers by a laser cutting process, but also can form a solar cell with high light absorption rate. .

In view of the above, the present invention provides a heterojunction solar cell for solving the problems of the prior art, comprising a solar cell body, a first patterned transparent conductive layer, and a second patterned transparent Conductive layer. The solar cell body comprises a semiconductor substrate, a first intrinsic amorphous germanium semiconductor layer, a first amorphous germanium semiconductor layer, a second intrinsic amorphous germanium semiconductor layer and a second amorphous germanium semiconductor layer. The semiconductor substrate has a first surface and a second surface disposed opposite to each other, and the semiconductor substrate is doped with a first semiconductor. The first intrinsic amorphous germanium semiconductor layer is disposed on the first surface. The first amorphous germanium semiconductor layer is disposed on the first intrinsic amorphous germanium semiconductor layer and doped with a second semiconductor. The second intrinsic amorphous germanium semiconductor layer is disposed on the second surface. The second amorphous germanium semiconductor layer is disposed on the second intrinsic amorphous germanium semiconductor layer and doped with a third semiconductor.

The first patterned transparent conductive layer is formed on the first amorphous germanium semiconductor layer and has a plurality of first extended cladding portions, and the first extended cladding portion is The edge of the first amorphous germanium semiconductor layer is partially covered. The second patterned transparent conductive layer is formed on the second amorphous germanium semiconductor layer, and the plurality of interconnected edges are exposed between the second patterned transparent conductive layer and the first patterned transparent conductive layer. a region, wherein the first patterned transparent conductive layer and the second patterned transparent conductive layer are insulated from each other by the interconnected edge exposure regions.

As described above, the first plurality of first extending cladding portions of the first patterned transparent conductive layer partially cover the edges of the first amorphous germanium semiconductor layer, thereby effectively increasing the light absorptivity of the solar cell body. That is, the edge of the solar cell body covered by the first extended cladding portion can also absorb light and generate photoelectric conversion, thereby increasing the output of current.

An auxiliary technical means derived from the above-mentioned necessary technical means is that the shape of the edge exposure zone is a rectangle, a square, an arc, an irregular shape, a ring shape or a combination thereof.

An auxiliary technical means derived from the above-mentioned technical means is that the second patterned transparent conductive layer has a plurality of second extended cladding portions, and the second extended cladding portion partially covers the second amorphous germanium semiconductor The edge of the layer. Thereby, the solar cell body absorbance can be relatively increased. Preferably, the first extended cladding portion is staggered with the second extended cladding portion.

An auxiliary technical means derived from the above-mentioned necessary technical means is that the edge of the first patterned transparent conductive layer is complementary to the edge pattern of the second patterned transparent conductive layer.

An auxiliary technical means derived from the above-mentioned necessary technical means is that the first semiconductor system is a first type semiconductor, one of the second semiconductor and the third semiconductor is a first type semiconductor, and the other is a second type. Semi-guide body. Preferably, the first type semiconductor is an N type semiconductor, and the second type semiconductor is a P type semiconductor; or the first type semiconductor is a P type semiconductor, and the second type semiconductor is an N type semiconductor.

The present invention further provides a method for fabricating a heterojunction solar cell, which comprises the following steps: step (a), preparing a semiconductor substrate, the semiconductor substrate doped with a first a semiconductor; step (b), forming a first intrinsic amorphous germanium semiconductor layer on a first surface of the semiconductor substrate; and (c) forming a first amorphous germanium semiconductor on the first intrinsic amorphous germanium semiconductor layer a layer, and the first amorphous germanium semiconductor layer is doped with a second semiconductor; in step (d), a second intrinsic amorphous germanium semiconductor layer is formed on a second surface of the semiconductor substrate; and step (e) is in the second Forming a second amorphous germanium semiconductor layer on the intrinsic amorphous germanium semiconductor layer, wherein the second amorphous germanium semiconductor layer is doped with a third semiconductor; and step (f) forming a first surface on the first amorphous germanium semiconductor layer Forming a transparent conductive layer, and the first patterned transparent conductive layer has a plurality of first extended cladding portions covering edges of the first amorphous germanium semiconductor layer; and step (g) is on the second amorphous germanium semiconductor layer Form a second picture The transparent conductive layer is formed, and a plurality of interconnected edge exposure regions are formed between the second patterned transparent conductive layer and the first patterned transparent conductive layer, so that the first patterned transparent conductive layer and the second patterned The transparent conductive layer is insulated from each other by edge contact regions that are in communication with each other. It should be particularly noted that the order of step (c) and step (d) can be reversed.

An auxiliary technical means derived from the above-mentioned technical means is that the first patterned transparent conductive layer and the second patterned transparent conductive layer are passed through a vacuum evaporation process, an arc discharge evaporation process, and a pulsed laser evaporation. plating A process or a sputtering process is formed.

An auxiliary technical means derived from the above-mentioned technical means is that when the first patterned transparent conductive layer is formed on the surface of the first amorphous germanium semiconductor layer, the step (f) is blocked by the mask or the semiconductor substrate holder. A portion of the surface of the amorphous germanium semiconductor layer, thereby forming a first extended cladding portion.

An auxiliary technical means derived from the above-mentioned technical means is that when step (g) forms a second patterned transparent conductive layer on the surface of the second amorphous germanium semiconductor layer, the second or second semiconductor transparent substrate is shielded by the mask or the semiconductor substrate holder. A portion of the surface of the amorphous germanium semiconductor layer further forms a plurality of second extended cladding portions, and the second extension portions are alternately arranged with the first extension portions.

An auxiliary technical means derived from the above-mentioned necessary technical means is that the first semiconductor system is a first type semiconductor, one of the second semiconductor and the third semiconductor is a first type semiconductor, and the other is a second type. semiconductor. Preferably, the first type semiconductor is an N type semiconductor, and the second type semiconductor is a P type semiconductor; or the first type semiconductor is a P type semiconductor, and the second type semiconductor is an N type semiconductor.

The specific embodiments of the present invention will be further described by the following examples and drawings.

PA100, PA200‧‧‧ Heterojunction twinned solar cells

PA1, PA1a‧‧‧ solar cell body

PA11‧‧‧crystalline semiconductor layer

PA12‧‧‧First essential amorphous germanium semiconductor layer

PA13‧‧‧First amorphous germanium semiconductor layer

PA14‧‧‧Second intrinsic amorphous germanium semiconductor layer

PA15‧‧‧Second amorphous germanium semiconductor layer

PA2, PA2a‧‧‧ transparent conductive layer

PA3‧‧‧ first electrode

PA4‧‧‧second electrode

100, 100a, 100b, 100c‧‧‧ heterojunction solar cells

1, 1a, 1b, 1c‧‧‧ solar cell body

11‧‧‧Semiconductor substrate

111‧‧‧ first surface

112‧‧‧ second surface

12‧‧‧First essential amorphous germanium semiconductor layer

13‧‧‧First amorphous germanium semiconductor layer

14‧‧‧Second intrinsic amorphous germanium semiconductor layer

15‧‧‧Second amorphous germanium semiconductor layer

2, 2a, 2b, 2c‧‧‧ first patterned transparent conductive layer

21, 21a, 21b, 21c‧‧‧ first extension cladding

3, 3a, 3b, 3c‧‧‧ second patterned transparent conductive layer

31, 31a, 31b, 31c‧‧‧ second extension cladding

ER1‧‧‧First edge exposure area

ER2‧‧‧Second edge exposure area

The first figure shows a schematic cross-sectional view of a heterojunction twin solar cell of the prior art; the second figure shows a schematic plan view of another heterojunction twin solar cell of the prior art; the third figure shows the first preferred embodiment of the present invention. The heterojunction provided by the example is too FIG. 4 is a schematic plan view showing a solar cell of a heterojunction according to a first preferred embodiment of the present invention; FIG. 5 is a schematic cross-sectional view showing a cross-sectional view of the AA of the third embodiment; FIG. 7 is a schematic plan view showing a BB cross-section of a third embodiment; FIG. 7 is a plan view showing a heterojunction solar cell according to a second preferred embodiment of the present invention; and FIG. 8 is a view showing a second preferred embodiment of the present invention. Another schematic plan view of a heterojunction solar cell; a ninth diagram showing a schematic view of a heterojunction solar cell provided by a third preferred embodiment of the present invention; and a tenth diagram showing a third preferred embodiment of the present invention Another schematic plan view of a heterojunction solar cell provided; FIG. 11 is a plan view showing a heterojunction solar cell according to a fourth preferred embodiment of the present invention; and a twelfth aspect showing the fourth aspect of the present invention Another schematic plan view of a heterojunction solar cell provided by the preferred embodiment.

Please refer to the third to sixth figures. The third figure shows a schematic plan view of the heterojunction solar cell provided by the first preferred embodiment of the present invention. The fourth figure shows the heterogeneity provided by the first preferred embodiment of the present invention. Another schematic plan view of the junction solar cell; the fifth diagram shows the AA cross-section of the third diagram; and the sixth diagram shows the BB cross-section of the third diagram.

As shown in the third and fourth figures, a heterojunction solar cell 100 The invention comprises a solar cell body 1, a first patterned transparent conductive layer 2 and a second patterned transparent conductive layer 3.

The solar cell body 1 includes a semiconductor substrate 11, a first intrinsic amorphous germanium semiconductor layer 12, a first amorphous germanium semiconductor layer 13, a second intrinsic amorphous germanium semiconductor layer 14, and a second amorphous germanium semiconductor layer. 15. The semiconductor substrate 11 has a first surface 111 and a second surface 112 disposed opposite to each other, and the semiconductor substrate 11 is doped with a first semiconductor. The first semiconductor is a first type semiconductor, and in the embodiment, the first type semiconductor is, for example, an N type semiconductor.

The first intrinsic amorphous germanium semiconductor layer 12 is disposed on the first surface 111. The first amorphous germanium semiconductor layer 13 is disposed on the first intrinsic amorphous germanium semiconductor layer 12 and doped with a second semiconductor. The second semiconductor is a second type semiconductor, and in the embodiment, the second type semiconductor is, for example, a P type semiconductor.

The second intrinsic amorphous germanium semiconductor layer 14 is disposed on the second surface 112. The second amorphous germanium semiconductor layer 15 is disposed on the second intrinsic amorphous germanium semiconductor layer 14 and doped with a third semiconductor. Wherein, the third semiconductor is a first type semiconductor, which is an N type semiconductor in this embodiment.

The first patterned transparent conductive layer 2 is formed on the first amorphous germanium semiconductor layer 13 and has a plurality of first extended cladding portions 21 partially covering the first amorphous portion The edges of the germanium semiconductor layer 13 and the second amorphous germanium semiconductor layer 15.

The second patterned transparent conductive layer 3 is formed on the second amorphous germanium semiconductor layer 15 and has a plurality of second extended cladding portions 31 partially covering the first amorphous portion矽 semiconductor layer 13 and second non The edge of the germanium semiconductor layer 15.

As described above, the first extended cladding portion 21 and the second extended cladding portion 31 are alternately arranged, and the edge of the first patterned transparent conductive layer 2 is complementary to the edge of the second patterned transparent conductive layer 3 but The plurality of mutually connected edge exposure regions are enclosed between the second patterned transparent conductive layer 3 and the first patterned transparent conductive layer 2, and the plurality of edge exposure regions are further divided into a plurality of edges. a first edge exposed area ER1 and a plurality of second edge exposed areas ER1, wherein the first edge exposed area ER1 is formed by the first extended covering portion 21 and the second extending covering portion 31 is located in the first extended package The covering portion 21 is surrounded by one of the two, and the second edge exposed portion ER2 is formed by the second extending covering portion 21, wherein the two adjacent first covering portions 31 are located in the second extending portion The covering portion 21 is surrounded by one of the two, and the plurality of first edge exposed regions ER1 and the plurality of second edge exposed regions ER2 are connected to each other, thereby making the first patterned transparent conductive layer 2 Arranging at intervals from the second patterned transparent conductive layer 3, that is, the first pattern is transparent The conductive layer 2 is completely out of contact with the edge of the second patterned transparent conductive layer 3 to avoid a short circuit phenomenon.

In addition, in the embodiment, the shape of the first edge exposure area ER1 is mainly a rectangle, and the shape of the second edge exposure area ER2 is mainly a rectangle and an arc located at four corners, but in other embodiments, To be limited thereto, for example, it may be a rectangle, a square, an arc, an irregular shape, a ring shape, or a combination thereof.

As described above, the plurality of first extending cladding portions 21 of the first patterned transparent conductive layer 2 partially cover the edges of the first amorphous germanium semiconductor layer 13 and the second amorphous germanium semiconductor layer 15 Can be effectively increased The light absorption rate of the solar cell body 1, that is, the edge of the solar cell body 1 covered by the first extended cladding portion 21 can also absorb light and generate photoelectric conversion, thereby increasing the output of current.

Please continue to refer to the third to sixth figures. As shown in the figure, the present invention further provides a method for fabricating a heterojunction solar cell 100, the first step of which is to prepare a semiconductor substrate 11, and the semiconductor substrate 11 is doped with a first semiconductor during fabrication, and the first semiconductor is In this embodiment, the first type of semiconductor, that is, the N-type semiconductor; then the first intrinsic amorphous germanium semiconductor layer 12 is formed on the first surface 111 of the semiconductor substrate 11 by a chemical vapor deposition process; A first amorphous germanium semiconductor layer 13 is formed on the amorphous germanium semiconductor layer by a chemical vapor deposition process, and the first amorphous germanium semiconductor layer 13 is doped with a second semiconductor, and the second semiconductor is in the present embodiment. In the example, a second type semiconductor, that is, a P-type semiconductor; a second surface 112 of the semiconductor substrate 11 is formed by a chemical vapor deposition process to form a second intrinsic amorphous germanium semiconductor layer 14; Forming a second amorphous germanium semiconductor layer 15 on the amorphous germanium semiconductor layer 14 by a chemical vapor deposition process, wherein the second amorphous germanium semiconductor layer 15 is doped with a third semiconductor, third In this embodiment, the conductor is a first type semiconductor, that is, an N type semiconductor; then a first patterned transparent conductive layer 2 is formed on the surface of the first amorphous germanium semiconductor layer 13, and the first patterned transparent conductive layer 2 has a plurality of first extended cladding portions 21 covering the edges of the first amorphous germanium semiconductor layer 13; finally, a second patterned transparent conductive layer 3 is formed on the second amorphous germanium semiconductor layer 15, and the second patterned transparent layer The conductive layer 3 and the first patterned transparent conductive layer 2 enclose a plurality of first edge exposed regions ER1 connected to each other And the second edge exposed region ER2, wherein the first patterned transparent conductive layer 2 and the second patterned transparent conductive layer 3 are disposed apart from each other, and the first amorphous germanium semiconductor layer 13 and the second amorphous germanium semiconductor layer 15 are disposed at intervals The edges are exposed from the first edge exposure zone ER1 and the second edge exposure zone ER2.

In this embodiment, the chemical vapor deposition process is, for example, a plasma-assisted chemical vapor deposition (PECVD) process, and the first patterned transparent conductive layer 2 and the second patterned transparent conductive layer 3 It is formed by a vacuum evaporation process, an arc discharge evaporation process, a pulsed laser evaporation process or a sputtering process.

In addition, in the forming process, the first extended cladding portion 21 of the first patterned transparent conductive layer 2 supports the edge of the second amorphous germanium semiconductor layer 15 of the solar cell body 1 by using a semiconductor substrate holder, and then forms a transparent conductive layer. The first patterned transparent conductive layer 2 is formed on the two sides of the bracket to form the first extended covering portion 21, so that the transparent conductive layer can be patterned by the shielding of the bracket to form the first patterned transparent conductive layer 2. The second extended cladding portion 31 of the second patterned transparent conductive layer 3 is, for example, a vacuum evaporation process, an arc discharge evaporation process, a pulsed laser evaporation process, or a sputtering process. The process is formed, that is, when formed, the mask covers the first amorphous germanium semiconductor layer 13 between the first extended cladding portion 21 and the first extended cladding portion 21 to form a second patterned transparent conductive The layer 3 and the second extension cladding portion 31. In this embodiment, the first extended covering portion 21 formed by the shield shielding is complementary to the pattern formed by the second extending covering portion 31 formed by the transparent mask, but the first extending covering portion 21 and the second extending portion The edges of the covering portion 31 are not connected, so that the first patterned transparent conductive layer 2 and the second patterned transparent can be avoided. The problem that the conductive layer 3 is in contact and short-circuited.

Please refer to the seventh and eighth figures. FIG. 7 is a schematic plan view showing a heterojunction solar cell according to a second preferred embodiment of the present invention; and FIG. 8 is a view showing the second preferred embodiment of the present invention. Another schematic diagram of a heterojunction solar cell. As shown, a heterojunction solar cell 100a includes a solar cell body 1a, a first patterned transparent conductive layer 2a, and a second patterned transparent conductive layer 3a. The heterojunction solar cell 100a is similar to the heterojunction solar cell 100 described above, and the difference is mainly that the first patterned transparent conductive layer 2a of the heterojunction solar cell 100a has four first extended cladding portions 21a, and The second patterned transparent conductive layer 3a has four second extended cladding portions 31a, and the first amorphous germanium semiconductor layer 13 and the second amorphous germanium semiconductor layer 15 are exposed from a region not covered by the patterned transparent conductive layer.

Please refer to the ninth and tenth drawings. The ninth drawing shows a schematic plan view of a heterojunction solar cell according to a third preferred embodiment of the present invention. The tenth figure shows the third preferred embodiment of the present invention. Another schematic diagram of a heterojunction solar cell. As shown, a heterojunction solar cell 100b includes a solar cell body 1b, a first patterned transparent conductive layer 2b, and a second patterned transparent conductive layer 3b. The heterojunction solar cell 100b is similar to the heterojunction solar cell 100 described above, and the difference is mainly that the first patterned transparent conductive layer 2b of the heterojunction solar cell 100b has four first extended cladding portions 21b, and The second patterned transparent conductive layer 3b has four second extended cladding portions 31b.

Referring to FIG. 11 and FIG. 12, FIG. 11 is a plan view showing a heterojunction solar cell according to a fourth preferred embodiment of the present invention; and FIG. 12 is a fourth preferred embodiment of the present invention. Another schematic plan view of a heterojunction solar cell provided by the embodiments. As shown, a heterojunction solar cell 100c includes a solar cell body 1c, a first patterned transparent conductive layer 2c, and a second patterned transparent conductive layer 3c. The heterojunction solar cell 100c is similar to the heterojunction solar cell 100 described above, and the difference is mainly that the first patterned transparent conductive layer 2c of the heterojunction solar cell 100c has four first extended cladding portions 21c, and The second patterned transparent conductive layer 3c does not have the second extended cladding portion. In the embodiment, the first patterned transparent conductive layer 2 is not in contact with the second patterned transparent conductive layer 3, so that the problem of short circuit can be avoided.

In summary, the heterojunction solar cell and the method for fabricating the same according to the present invention are formed by using a bracket and/or a mask to form a first patterned transparent conductive layer, and forming a second pattern transparent. When the conductive layer is shielded by the mask, the first patterned amorphous conductive layer and the second patterned transparent conductive layer are formed to expose the first amorphous germanium semiconductor layer 13 and the second amorphous germanium semiconductor layer at the shielding portion. And forming a first extended cladding portion or a second extended cladding portion on both sides of the shielding portion, thereby increasing the photoelectric conversion efficiency of the solar cell body, and due to the first extended cladding portion or the second extended cladding portion It is not in direct contact, so there is no short circuit or leakage current. Compared with the prior art heterojunction solar cell, after forming a transparent conductive layer and separating two transparent conductive layers by laser cutting, the present invention can effectively omit the laser cutting system. At the same time, the edge of the solar cell body is only partially blocked, so that the transparent conductive layer can cover the area of the solar cell body, thereby effectively increasing the absorbance and photoelectric conversion rate of the solar cell body.

In addition, in this embodiment, the first semiconductor and the third semiconductor are a first type semiconductor, the second semiconductor is a second type semiconductor, and the first type semiconductor is an N type semiconductor, and the second type semiconductor is a P type semiconductor; However, in other embodiments, the first semiconductor and the second semiconductor are first type semiconductors, the third semiconductor is a second type semiconductor, and the first type semiconductor may be a P type semiconductor, and the second type semiconductor It can also be opposed to an N-type semiconductor.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed.

100‧‧‧Hexual junction solar cells

1‧‧‧ solar cell body

2‧‧‧First patterned transparent conductive layer

21‧‧‧First extension cladding

ER1‧‧‧First edge exposure area

Claims (15)

A heterojunction solar cell comprising: a solar cell body, comprising: a semiconductor substrate having a first surface and a second surface disposed oppositely, and the semiconductor substrate is doped with a first semiconductor; a first essence An amorphous germanium semiconductor layer is disposed on the first surface; a first amorphous germanium semiconductor layer is disposed on the first intrinsic amorphous germanium semiconductor layer and doped with a second semiconductor; a second essence An amorphous germanium semiconductor layer is disposed on the second surface; and a second amorphous germanium semiconductor layer is disposed on the second intrinsic amorphous germanium semiconductor layer and doped with a third semiconductor; The patterned transparent conductive layer is formed on the first amorphous germanium semiconductor layer and has a plurality of first extended cladding portions, and the first extended cladding portions are coated on the first amorphous germanium An edge of the semiconductor layer; and a second patterned transparent conductive layer formed on the second amorphous germanium semiconductor layer, and the second patterned transparent conductive layer and the first patterned transparent conductive layer are bound Construct A plurality of communication with each other edge of the exposed portion, whereby the first pattern of the transparent conductive layer and the second transparent conductive layer patterned by the plurality of communication with each other edge of the exposed region insulated from each other. The heterojunction solar cell of claim 1, wherein the edge exposure regions are rectangular, square, curved, irregular, annular, or a combination thereof. The heterojunction solar cell of claim 1, wherein the second patterned transparent conductive layer has a plurality of second extended cladding portions, the second extended cladding portions are overlaid on The edge of the second amorphous germanium semiconductor layer. The heterojunction solar cell of claim 3, wherein the first extended cladding portions are alternately arranged with the second extended cladding portions to cause the first patterned transparent conductive layer to be The edges are complementary to the edges of the second patterned transparent conductive layer but are not interconnected. The heterojunction solar cell of claim 1, wherein an edge of the first patterned transparent conductive layer is complementary to an edge pattern of the second patterned transparent conductive layer. The heterojunction solar cell of claim 1, wherein the first semiconductor is a first type semiconductor, and the second semiconductor and the third semiconductor are a first type semiconductor, and One is a second type semiconductor. The heterojunction solar cell according to claim 6, wherein the first type semiconductor is an N type semiconductor, and the second type semiconductor is a P type semiconductor. A heterojunction solar cell as described in claim 6 of the patent application, wherein The first type semiconductor is a P type semiconductor, and the second type semiconductor is an N type semiconductor. A method for fabricating a heterojunction solar cell, comprising the steps of: (a) preparing a semiconductor substrate doped with a first semiconductor; and (b) forming a first essence on a first surface of the semiconductor substrate An amorphous germanium semiconductor layer; (c) forming a first amorphous germanium semiconductor layer on the first intrinsic amorphous germanium semiconductor layer, and the first amorphous germanium semiconductor layer is doped with a second semiconductor; (d) Forming a second intrinsic amorphous germanium semiconductor layer on a second surface of the semiconductor substrate; (e) forming a second amorphous germanium semiconductor layer on the second intrinsic amorphous germanium semiconductor layer, wherein the second amorphous The first semiconductor transparent conductive layer has a first patterned extended conductive package a first extension cladding portion is disposed on the edge of the first amorphous germanium semiconductor layer; and (g) forming a second patterned transparent conductive on the second amorphous germanium semiconductor layer Layer, and the second pattern is transparent and conductive Forming a plurality of interconnected edge exposure regions between the first patterned transparent conductive layer, wherein the first patterned transparent conductive layer and the second patterned transparent conductive layer are interconnected by the plurality of interconnected transparent conductive layers The edge exposure areas are insulated from each other. The method for fabricating a heterojunction solar cell according to claim 9, wherein the first patterned transparent conductive layer and the second patterned transparent guide The electrical layer is formed by a vacuum evaporation process, an arc discharge evaporation process, a pulsed laser evaporation process, or a sputtering process. The method for fabricating a heterojunction solar cell according to claim 9, wherein the step (f) is to form the first patterned transparent conductive layer on the surface of the first amorphous germanium semiconductor layer. The cover or the semiconductor substrate holder blocks the edge exposure regions to form the first extension cladding portions. The method for fabricating a heterojunction solar cell according to claim 9, wherein the step (g) is to form the second patterned transparent conductive layer on the surface of the second amorphous germanium semiconductor layer. The cover or the semiconductor substrate holder blocks the edge exposure regions to form a plurality of second extension cladding portions. The method of fabricating a heterojunction solar cell according to claim 9, wherein the first semiconductor is a first type semiconductor, and the second semiconductor and the third semiconductor are a first type. The semiconductor, the other is a second type semiconductor. The method of fabricating a heterojunction solar cell according to claim 13, wherein the first type semiconductor is an N type semiconductor, and the second type semiconductor is a P type semiconductor. The method of fabricating a heterojunction solar cell according to claim 13, wherein the first type semiconductor is a P type semiconductor, and the second type semiconductor is an N type semiconductor.