Tellurium schottky barrier contact for amorphous silicon solar cells

• US 4,213,798 A
• Filed: 04/27/1979
• Issued: 07/22/1980
• Est. Priority Date: 04/27/1979
• Status: Expired due to Term

• Current Assignee: RCA Corporation
• Original Assignee: RCA Corporation
• Inventors: Williams, Richard, Arie, Yehuda
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US06/033,967
• Time in Patent Office: 452 Days
• Field of Search: 136/89 SJ, 136/89 TF, 357/2, 357/15, 357/16, 357/30, 427/74, 427/250
• US Class Current: 136/255
• CPC Class Codes: H01L 31/03921 including only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/07 the potential barriers being only of the Schottky type
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A Schottky barrier amorphous silicon solar cell incorporates a tellurium layer as the Schottky barrier.

Claims

1. In a Schottky barrier solar cell which comprises an electrically conductive substrate, a body of hydrogenated amorphous silicon having regions of differing conductivity, said body having opposed major surfaces wherein one of said major surfaces ohmically contacts said substrate, and a layer of material forming a Schottky barrier with said body contiguous to a major surface of said body opposite to said substrate, the improvement wherein the material which forms the Schottky barrier is a layer of tellurium.

2. The solar cell according to claim 1 wherein said tellurium layer has a thickness of from about 5 to about 25 nanometers.

3. The solar cell according to claim 1 wherein said body of hydrogenated amorphous silicon has two regions of differing conductivity.

4. The solar cell according to claim 3 wherein said body comprises a region of N⁺ -type conductivity hydrogenated amorphous silicon which contacts said substrate and a region of intrinsic hydrogenated amorphous silicon which contacts said N⁺ -type region and said tellurium layer.

5. The solar cell according to claim 4 wherein the tellurium layer has a thickness of from about 5 to about 25 nanometers.

6. The solar cell according to claim 1 wherein a metal or transparent conductor layer overlies said tellurium layer.

7. The solar cell according to claim 6 wherein said metal or transparent conductor layer is selected from the group consisting of platinum, aluminum, indium, gold, PtSiO₂, and indium tin oxide.

8. In a Schottky barrier hydrogenated amorphous silicon solar cell which comprises an electrically conductive substrate, a body of hydrogenated amorphous silicon ohmically contacting said substrate, and a material forming a Schottky barrier with said body of hydrogenated amorphous silicon, the improvement wherein the material which forms the Schottky barrier is tellurium.

9. The solar cell according to claim 8 wherein said tellurium is in the form of a layer from about 5 to about 25 nanometers thick.

10. The solar cell according to claim 9 wherein a transparent metal or transparent conductor layer overlies said layer of tellurium.

11. A method of increasing the open circuit voltage of a platinum Schottky barrier hydrogenated amorphous silicon solar cell which comprises an electrically conductive substrate, a body of hydrogenated amorphous silicon ohmically contacting said substrate, and a platinum Schottky barrier layer contacting said body of hydrogenated amorphous silicon, comprising interposing a layer of tellurium between said body of hydrogenated amorphous silicon and said platinum Schottky barrier metal layer.

12. The method according to claim 11 wherein said tellurium layer has a thickness of from about 5 to about 25 nanometers.

13. The method according to claim 12 wherein said tellurium is evaporated onto said body by heating the tellurium to a temperature of from about 500°

to about 600°

C. at a pressure of from about 10^-4 to about 10^-5 Torr.