JPS6214954B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar cell using an amorphous semiconductor such as amorphous silicon, and is particularly aimed at improving the characteristics thereof.

The figure shows an embodiment of the present invention, in which 1 is a transparent insulating substrate such as glass, 2a, 2b, 2c are first electrodes arranged in a predetermined direction on the substrate, 3a, 3
b, 3c are amorphous silicon layers deposited on the first electrodes 2a, 2b, 2c, respectively; 4a, 4b, 4c are the second amorphous silicon layers deposited on the amorphous silicon layers 3a, 3b, 3c, respectively. The electrode 5 is an insulating film that tightly surrounds the laminate of the first electrode, the amorphous silicon layer, and the second electrode from the second electrode side.

Each of the first electrodes and each of the second electrodes adjacent thereto have extension portions 10 and 11 extending in the arrangement direction between adjacent opposing sides, and are overlapped and connected at the extension portions. There is. More specifically, between the plurality of first electrodes 2a, 2b, 2c arranged on the insulating substrate 1, the first electrodes 2a, 2b, 2c, amorphous silicon layers 3a, 3b, 3c and second electrodes 4a, 4b, 4
Power generation areas 12a, 12b, 1 made of a laminate of c.
The adjacent amorphous silicon layers 3a and 3b on the left side of the layer 2c extend to fill the space between the adjacent opposing layers. Then, amorphous silicon layers 3a and 3b fill the gap between adjacent power generating areas 12a and 12b on the left.
The extended portions 11, 11 of the second electrodes 4a, 4b do not touch the insulating substrate 1 beyond the extended portions of the amorphous silicon layers 3a, 3b, but extend to the first electrodes 2b of the power generation areas 12b, 12c on the right. , 2c extension 1
Electrical connection is established by falling to 0 and 10.

In this way, the first electrode 2 of the power generation areas 12a, 12b on the left to the power generation areas 12b, 12c on the right
The extensions 11, 11 of the second electrodes 4a, 4b extending toward the extensions 10, 10 of b, 2c extend beyond the right ends of the amorphous silicon layers 3a, 3b, creating a large step that may cause a disconnection accident. Then, instead of falling once onto the surface of the insulating substrate 1, it falls directly onto the extensions 10, 10 of the first electrodes 2b, 2c, where the step difference is alleviated by the film thickness of the first electrodes 2b, 2c. Wire breakage accidents caused by such large steps are prevented.

The first electrode has translucency and is made of tin oxide, indium oxide, indium tin oxide (In ₂ O ₃ +xSnO ₂ ,
X≦0.1), and the second electrode is made of aluminum, chromium, or the like.

The amorphous silicon layer generates electrons and/or holes that contribute to power generation when irradiated with light. Specifically, the amorphous silicon layer includes a P-type layer, a non-doped layer, and an N-type layer that are sequentially stacked from the first electrode side. It has a three-layer structure. Such an amorphous silicon layer is sequentially deposited by glow discharge in an atmosphere containing silicon compound gas such as silane and P-type and N-type impurity gases. The above P-type layer has a thickness of 40 to 1000 Å and a dove amount.
0.01~1%, non-doped layer thickness 0.5~2μm,
The N-type layer has a thickness of 200 to 1000 Å and a dope amount of 0.1 to 3%.

In the above device, when light enters the amorphous silicon layer via the substrate 1 and the first electrode, free state electrons and/or holes are generated mainly in the non-doped layer, and these are caused by the PIN junction electric field created by each layer. After being pulled by and moving, it is collected at the opposing first and second electrodes, and a voltage is generated between the two electrodes. At this time, the second electrode 4a on the left, the first electrode 2b in the center,
The second electrode 4b at the center and the first electrode 2c at the right side are electrically connected, so that the electromotive voltages between the opposing electrodes are added in series.

The insulating film 5 is made of silicon oxide, silicon nitride, etc., and is formed by glow discharge in an atmosphere containing silane gas and oxygen or nitrogen gas, or by reactive sputtering in which quartz glass is sputtered in an argon and oxygen or nitrogen gas atmosphere. It can be formed by Such an insulating film provides mechanical protection for the device, completely shields the second electrode and the amorphous silicon layer from the outside world, and protects the device from moisture, corrosive gases, and the like.

Although the device in the above embodiment was of the PIN junction type, a shotgun type could also be implemented.Also, in the device of the embodiment, light was incident from the glass substrate 1 side, but the insulating film 5 and the second electrodes 4a, 4b, 4c were By making it transparent, light can also be incident from the insulating film 5 side.

Now, if light is incident on the solar cell and a load is connected, for example, between the first electrode 2a on the left end and the second electrode 4c on the right end, a current based on the photovoltaic voltage of the solar cell will flow to the load. , the photoelectric conversion efficiency at this time depends on the internal resistance of the solar cell. Such internal resistance is mainly caused by each power generation area 12a, 12b, 12c when one power generation area is composed of a pair of first and second electrodes and an amorphous silicon layer interposed between these electrodes. The resistance is determined by the series resistance between them, and the smaller the better, but in the solar cell according to the embodiment of the present invention, the adjacent first and second electrodes have extension portions 10 extending in the arrangement direction, 11, the electrical connection between each power generation area is perpendicular to the above arrangement direction (i.e., the direction perpendicular to the paper in Fig. 1).
For example, it can be carried out over the shortest distance and sufficient length, such as across the entire width of each power generation area (L in Figure 2), and the current between each area can be concentrated in one part. It is possible to reduce the series resistance between each power generation area.

As is clear from the above explanation, according to the present invention, in a solar cell using an amorphous semiconductor and consisting of a plurality of power generation regions, the series resistance between each power generation region can be sufficiently reduced, and the photoelectric conversion efficiency can be increased. can be obtained. Further, since the series resistance between the power generation sections is small, the number of series stages of each power generation section can be easily increased, and a solar cell with a higher output voltage can be realized. Furthermore, a second electrode extension extending from one power generation area toward the first electrode extension of the other power generation area between adjacent opposing first electrodes,
Rather than going beyond the side edge of the amorphous semiconductor layer and falling down a large step corresponding to the thickness of the semiconductor layer and once dropping to the surface of the insulating substrate, the step is alleviated by the thickness of the first electrode. Since the first electrodes fall directly on the extended portions of the first electrodes, it is possible not only to prevent disconnection accidents caused by such large steps, but also to ensure insulation between adjacent first electrodes.
Therefore, it is possible to reduce the distance between the adjacent facing units, and increase the proportion of the light-receiving area occupied by the power generation area.

[Brief explanation of the drawing]

1 and 2 are a sectional view and a perspective view, respectively, showing an embodiment of the present invention. 1...Substrate, 3a, 3b, 3c...Amorphous silicon layer, 5...Insulating film.

Claims (1)

[Claims] 1 A plurality of first electrodes arranged on an insulating substrate, an amorphous semiconductor layer and a second electrode corresponding to each of the first electrodes and sequentially deposited on each of the first electrodes; The second electrodes are connected to each other in an overlapping manner so as to extend in the arrangement direction between adjacent second electrodes, and the plurality of first electrodes arranged on the insulating substrate are arranged in one power generation area. The amorphous semiconductor layer constituting the amorphous semiconductor layer extends to fill the gap between the adjacent opposing sides, and the extended portion of the second electrode of one power generation area contacts the insulating substrate beyond the extended portion of the amorphous semiconductor layer. A solar cell characterized in that the first electrode extension part of the other power generation area falls without falling.