PHOTOVOLTAIC DEVICE AND METHODS OF FORMING THE SAME
Methods and devices are described for a photovoltaic device. The photovoltaic device includes a glass substrate, a semiconductor absorber layer formed over the glass substrate, a metal back contact layer formed over the semiconductor absorber layer, and a p-type back contact buffer layer formed from one of MnTe, Cd 1-x Mn x Te, and SnTe, the buffer layer disposed between the semiconductor absorber layer and the metal back contact layer.
1 . A method of manufacturing a photovoltaic device comprising the steps of:
depositing a semiconductor absorber layer on a substrate, wherein the semiconductor absorber layer is formed from CdTe;
depositing a p-type back contact buffer layer on the semiconductor absorber layer, wherein the depositing a p-type back contact buffer layer step is a sputtering step whereby the p-type back contact buffer layer is deposited on the semiconductor absorber layer by sputtering Cd 1-x Mn x Te onto the semiconductor absorber layer; and
depositing a back contact layer on the p-type back contact buffer layer.
2 . The method of claim 1 , wherein the sputtering step is performed at a temperature of up to about 300° C.
3 . The method of claim 1 , wherein the back contact buffer layer has a thickness from about 10 nm to about 500 nm.
4 . The method of claim 1 , wherein the Cd 1-x Mn x Te comprises Cd 0.5 Mn 0.5 Te.
5 . The method of claim 1 , wherein the back contact layer is a metal back contact layer.
6 . The method of claim 5 , wherein the back contact buffer layer is deposited directly on the p-type back contact buffer layer.
7 . The method of claim 1 , wherein the back contact layer is selected from a group consisting of MoN x /Al, ZnTe:Cu, CdSe, MgTe, HgTe, and ZnTe/Al.
8 . The method of claim 7 , wherein the back contact buffer layer is deposited directly on the p-type back contact buffer layer.
9 . The method of claim 1 , wherein the back contact buffer layer is deposited directly on the p-type back contact buffer layer.