JPH021991A - Photoelectric conversion device - Google Patents

Abstract

PURPOSE:To prevent a photoelectric conversion efficiency from decreasing due to the shielding of incident light even if a structure is made sufficiently large in area by a method wherein the structure formed of an opaque or a semi-transparent material, which shields light rays, is provided to the surface, and the structure is so formed as to make parts between grooves protrudent along the grooves formed on the surface of the structure. CONSTITUTION:A substrate 1 is composed of a p-type single crystal silicon 5 and an n-type semiconductor layer 4 both formed on its surface through a thermal diffusion method. A rear electrode 6 formed of Ti and Ag is formed on the rear. V-shaped grooves, formed in two directions which cross each other, are provided on the surface, and an electrode 2 of Ti and Ag is formed on the protrudent part of the grooves arranged along one of two directions. The pitch of the V-shaped grooves, extending perpendicularly to the electrode 2, is 20mum, that of the V-shaped grooves under the electrode 2 is 800mum, and the electrode 2 is 2mum in thickness. The V-shaped grooves are formed in such a manner that single crystal silicon is subjected to an anisotropic etching with an alkali solution. In this structure, the area occupied by an electrode is 3% or so of that of the whole photoelectric conversion device, but the loss of an incident light volume due to the shielding of the incident light by the electrode can be reduced to 1% or so.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a photoelectric conversion device having a structure on its surface that blocks light, and particularly to a photoelectric conversion device having a structure suitable for improving photoelectric conversion efficiency.

[Conventional technology]

Some conventional photoelectric conversion devices suppress loss of incident light due to electrodes by minimizing electrode area. These devices include, for example, Applied Physics
Letters Volume 48 (3).

20. January 1986 20 shares (APPl, Phys.

Lett,,'Vo1.48 (3), 20. Jan,
1986).

[Problem to be solved by the invention]

The above conventional technology takes a measure to reduce the time t at which incident light on the device surface is blocked by a structure such as an electrode by minimizing the area of the structure, and the area of the structure is large. There was a problem that I couldn't do.

An object of the present invention is to provide a structure of a photoelectric conversion device that does not reduce photoelectric conversion efficiency due to blocking of incident light even if the area of the structure is made sufficiently large.

[Means to solve the problem]

The above object is a photoelectric conversion device that performs photoelectric conversion by making light incident on the surface, which has a structure made of an opaque or translucent material that blocks light on the surface, and the structure is connected to grooves formed on the surface. This is achieved by forming the convex portions between the grooves along the grooves.

[Effect]

The operation of the present invention will be explained using the drawings. FIG. 1 shows the case where electrodes are formed on the convex portions of the groove structure on the surface of the device.

FIG. 2 shows its cross-sectional view. A portion 3 of the light incident on the surface of the device 1 hits the electrode 2. If the electrode 2 is opaque or translucent, all or part of the light impinging on the electrode 2 will not enter the device 1 below the electrode. Conventionally, the third As shown in FIG. 4, since the electrode 2 was formed on a flat portion of the device surface, the light reflected on the electrode surface was reflected into the air, reducing the photoelectric conversion efficiency accordingly. On the other hand, in the structure shown in FIG. 2, the incident light 3 enters the photoelectric conversion device 1 again, so that the loss of the incident light due to the electrode 2 is reduced. Needless to say, in order to minimize the loss, it is necessary to increase the light reflectance of the surface of the electrode 2. Further, in the above description, the structure on the surface of the device is described as the electrode 2, but the same holds true for structures other than electrodes. Also, board 1 in Figure 1
may be any structure having a photoelectric conversion function. - Examples of boat fishing include monocrystalline silicon semiconductors with pn junctions, and polycrystalline silicon.

There are those in which a pn junction is formed in amorphous silicon, and those in which a ■-■ group compound or a ■-■ group compound is used instead of silicon.

FIG. 5 shows an example in which electrodes are formed only on one side of the groove. In this case as well, the light that has entered the electrode 2 enters the photoelectric conversion device 1 again.

Although the groove structure having a triangular cross-section has been described above, the cross-sectional shape may also be a trapezoid or a curved shape as shown in FIG. Further, the grooves do not necessarily have to be straight lines, but may be curved lines or broken lines, and furthermore, the grooves may intersect with each other.

The above invention is particularly effective when high photoelectric conversion efficiency is required, such as in solar cells.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. For the substrate 1, ρ-type crystalline silicon 5 was used, on the surface of which an n-type semiconductor layer 4 was formed by a thermal diffusion method.

A back electrode 6 made of Ti and Ag was formed on the back surface. V-shaped grooves were formed on the surface in two directions that crossed each other, and electrodes 2 made of Ti and Ag were formed on the convex portions of the grooves in one direction. The pitch of the V-shaped groove is 20 μm for the groove running perpendicular to the electrode.
, the groove at the bottom of the electrode is 800 μm, and the thickness of the electrode is 2 μm. To form the V-shaped groove, anisotropic etching of single crystal silicon using an alkaline etching solution was used. In this structure, although the area occupied by the electrode in the entire photoelectric conversion device is about 3%, the loss of the amount of incident light due to the blocking of incident light by the electrode could be suppressed to about 1%.

〔Effect of the invention〕

According to the present invention, even if there is a structure on the surface of a photoelectric conversion device that blocks light, the loss of the amount of incident light can be reduced by forming this on the groove structure.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams of an example of the structure of a photoelectric conversion device according to the present invention, FIGS. 3 and 4 are sectional views showing the structure of a conventional photoelectric conversion device, and FIGS. 5 and 6 and the seventh
The figure is a diagram for explaining still another embodiment of the present invention. 1... Substrate, 2... Electrode, 3... Incident light.

Claims (1)

[Claims] 1. A photoelectric conversion device that performs photoelectric conversion by making light incident on a surface, which has a structure made of an opaque or translucent material that blocks light on the surface, and the structure is attached to the surface. A photoelectric conversion device characterized in that it is formed along the formed grooves and on convex portions between the grooves. 2. The photoelectric conversion device according to claim 1, wherein the structure is formed only on one side of the groove. 3. The photoelectric conversion device according to claim 1 or 2, wherein the structure is an electrode. 4. The photoelectric conversion device according to claim 1, 2, or 3, wherein the groove is formed as an antireflection structure.