Patent ID: 8859321
Filing Date: 2014-10-14
Classification: H01L,Y02E

Abstract:
1. A method for fabrication of a tandem photovoltaic device, comprising: forming a bottom cell having an N-type layer, a P-type layer and a bottom intrinsic layer therebetween; and forming a top cell relative to the bottom cell, the top cell having an N-type layer, a P-type layer and a top intrinsic layer therebetween; wherein the top intrinsic layer is formed from an undoped material at a first deposition temperature and the bottom intrinsic layer is formed at a second deposition temperature that is different from the first deposition temperature such that a different band gap energy is achieved for each layer by adjusting the deposition temperature so that the band gap energy for the top intrinsic layer is different than that of the bottom intrinsic layer; wherein the band gap energies are controlled by adjusting only the deposition temperature, and the band gap energy for the bottom intrinsic layer is lower than the band gap energy for the top intrinsic layer; and wherein the top intrinsic layer is deposited at a first temperature and the bottom intrinsic layer is deposited at a lower temperature.