Patent ID: 8084682

Claim:
A heterojunction photovoltaic device comprising: an optically transparent substrate for receiving incident light; a front contact formed of a transparent conductive oxide disposed on the side of said optically transparent substrate opposite incident light; an n-type window layer having a band gap energy of at least 2.2 eV disposed on said front contact; a p-type absorber structure deposited contiguously onto said n-type window layer, wherein said p-type absorber structure comprises three absorber layers in sequential touching contact, a first absorber of said three absorber layers is selected from the group consisting of CdSe, Cd 1-y Mg y Te, Cd 1-y Mn y Te and Cd 1-y Zn y Te, where y ranges from about 0.05 to about 0.20, a second absorber layer of said three absorber layers is CdTe and a third absorber layer of said three absorber layers is Cd 1-z Hg z Te, where z ranges from about 0.15 to about 0.20, the first absorber layer is in contiguous contact with said n-type window layer, the band gap energy progressively decreases from the first absorber layer to the last absorber layer; and a back contact formed on the last absorber layer of said p-type absorber structure.