Absorber Layer for a Thin Film Photovoltaic Device With a Double-Graded Band Gap

摘要

A gallium-containing alloy is formed on the light-receiving surface of a CIGS absorber layer, and, in conjunction with a subsequent selenization or anneal process, is converted to a gallium-rich region at the light-receiving surface of the CIGS absorber layer. A second gallium-rich region is formed at the back contact surface of the CIGS absorber layer during selenization, so that the CIGS absorber layer has a double-graded gallium concentration that increases toward the light-receiving surface and toward the back contact surface of the CIGS absorber layer. The double-graded gallium concentration advantageously produces a double-graded bandgap profile for the CIGS absorber layer.

主权项

1. A method of forming a thin-film solar cell absorber layer, the method comprising:
forming a first layer above the substrate, wherein the first layer comprises copper, indium, gallium, and selenium; forming a second layer above the first layer, wherein the second layer is formed using trimethyl gallium (TMGa) and a selenium-containing gas; and heating the first layer and the second layer.