Method of fabricating high-efficiency Cu(In,Ga)(SeS).sub.2 thin films for solar cells

US5441897A · kind A · utility

Assignee

• Midwest Research Institute, Inc. · US

Inventors

• Rommel Noufi · Golden, US
• Andrew Gabor · Boulder, US
• John R. Tuttle · Boulder, US
• Andrew L. Tennant · Denver, US
• Miguel A. Contreras · Golden, US
• David S. Albin · Denver, US
• Jeffrey J. Carapella · Evergreen, US

Key dates

• Filing date: Feb 16, 1994
• Grant date: Aug 15, 1995
• Expiry date: Feb 16, 2014

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P70/50

Abstract

A process for producing a slightly Cu-poor thin film of Cu(In,Ga)(Se,S).sub.2 comprises depositing a first layer of (In,Ga).sub.x (Se,S).sub.y followed by depositing just enough Cu+(Se,S) or Cu.sub.x (Se,S) to produce the desired slightly Cu-poor material. In a variation, most, but not all, (about 90 to 99%) of the (In,Ga).sub.x (Se,S).sub.y is deposited first, followed by deposition of all the Cu+(Se,S) or Cu.sub.x (Se,S) to go near stoichiometric, possibly or even preferably slightly Cu-rich, and then in turn followed by deposition of the remainder (about 1 to 10%) of the (In,Ga).sub.x (Se,S).sub.y to end with a slightly Cu-poor composition. In yet another variation, a small portion (about 1 to 10%) of the (In,Ga).sub.x (Se,S).sub.y is first deposited as a seed layer, followed by deposition of all of the Cu+(Se,S) or Cu.sub.x (Se,S) to make a very Cu-rich mixture, and then followed deposition of the remainder of the (In,Ga).sub.x (Se,S).sub.y to go slightly Cu-poor in the final Cu(In,Ga)(Se,S).sub.2 thin film.