Method of forming photovoltaic quality amorphous alloys by passivating defect states

US4569697A · kind A · utility

Assignee

• Energy Conversion Devices, Inc. · US

Inventors

• Raphael Tsu · Huntersville, US
• Stanford R. Ovshinsky · Bloomfield Hills, US
• Jesus Hernandez · Oxnard, US
• Denis Martin · Clermont-Ferrand, FR

Key dates

• Filing date: Aug 26, 1983
• Grant date: Feb 11, 1986
• Expiry date: Aug 26, 2003

Classification

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

Abstract

Relatively dense, photovoltaic quality amorphous alloys which are characterized by reduced density of defect states in the band gaps thereof and which are particularly suited for use in tandem photovoltaic devices are formed by evaporating amorphous germanium and amorphous silicon in an ultrahigh vacuum environment, diffusing a density of states reducing element into and through the amorphous material, and finally annealing the resultant amorphous alloy to complete the diffusion process. The amorphous alloy, so formed, is a substantially contaminant-free, substantially tetrahedrally coordinated material. Fluorine is the preferred density of states reducing element which is added to the amorphous material for reducing the density of states through compensation, and for orbital promotion and expansion.