Thin film solar cell and method for manufacturing the same

• US 5,858,121 A
• Filed: 09/11/1996
• Issued: 01/12/1999
• Est. Priority Date: 09/13/1995
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Wada, Takahiro, Nishitani, Mikihiko, Kohara, Naoki
• Primary Examiner(s): NGUYEN, NAM X
• Application Number:
  US08/712,025
• Time in Patent Office: 853 Days
• Field of Search: 136/265, 136/264, 438/95
• US Class Current: 136/265
• CPC Class Codes: H01L 31/0322 comprising only AIBIIICVI chalcopyrite compounds, e.g. Cu In Se2, Cu Ga Se2, Cu In Ga Se2
• CPC Class Codes: H01L 31/0749 including a AIBIIICVI compound, e.g. CdS/CulnSe2 [CIS] heterojunction solar cells
• CPC Class Codes: Y02E 10/541 CuInSe2 material PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A thin film solar cell having high conversion efficiency is provided. The band gap of the thin film solar cell can be controlled while keeping the quality superior to conventional solar cells. The absorber layer for photovoltaic energy conversion is a Cu(In_1-X Ga_X)(Se_1-Y S_Y)₂ based solid solution where X and Y are in the range of the following Equation:

0.317+0.176Y≧X≧0.117+0.176Y

1>X+Y>0

Y>0,

The Cu(In_1-X Ga_X)(Se_1-Y S_Y)₂ based solid solution has a specific chalcopyrite type crystal structure and its lattice constant ratio of c-axis to a-axis is extremely close to two. It is most preferable that the band gap is 1.4 eV, X is 0.3, and Y is 0.4, since the conversion efficiency of a homojunction solar cell will then become a maximum.

Claims

1. A thin film solar cell comprising an absorber layer of Cu(In_1-X Ga_X) (Se_1-Y S_Y)₂ for photovoltaic energy conversion, where X and Y are in the range indicated by the following Equation (1):

space="preserve" listing-type="equation">0.317+0.176Y≧

X≧

0.117+0.176Y (1)

space="preserve" listing-type="equation">1>

X+Y>

0

space="preserve" listing-type="equation">Y>

0.

2. The thin film solar cell according to claim 1, wherein X and Y are in the range indicated by the following Equation (2):

space="preserve" listing-type="equation">X=0.217+0.176Y (2)

space="preserve" listing-type="equation">1>

X+Y>

0

space="preserve" listing-type="equation">Y>

0.

3. The thin film solar cell according to claim 1, where X=0.3 and Y=0.4.

4. The thin film solar cell according to claim 1, wherein the absorber layer of Cu(In_1-X Ga_X)(Se_1-Y S_Y)₂ has a chalcopyrite type crystal structure, wherein the lattice constant ratio of c-axis to a-axis is about two.

5. A method for manufacturing a thin film solar cell having an absorber layer of Cu(In_1-X Ga_X)(Se_1-Y S_Y)₂ for photovoltaic energy conversion, where X and Y are in the range of the following Equation (1),

6. A method for manufacturing a thin film solar cell having an absorber layer of Cu(In_1-X Ga_X)(Se_1-Y S_Y)₂ for photovoltaic energy conversion, where X and Y are in the range of Equation (1),

View Dependent Claims (7)

7. The method for manufacturing a thin film solar cell according to claim 6, wherein the In sulfide is In₂ S₃.

8. A method for manufacturing a thin film solar cell having an absorber layer of Cu(In_1-X Ga_X)(Se_1-Y S_Y)₂ for photovoltaic energy conversion, where X and Y are in the range of Equation (1),

View Dependent Claims (9)

9. The method for manufacturing a thin film solar cell according to claim 8, wherein the Ga sulfide is GaS.