Novel Contact Materials for Improved Performance CdTe Solar Cells Final Report

Abstract

This program has explored a number of novel materials for contacts to CdTe solar cells in order to reduce the back contact Schottky barrier to zero and produce an ohmic contact. The project tested a wide range of potential contact materials including TiN, ZrN, CuInSe2:N, a-Si:H and alloys with C, and FeS2. Improved contacts were achieved with FeS2. As part of understanding the operation of the devices and controlling the deposition processes, a number of other important results were obtained. In the process of this project and following its conclusion it led to research that resulted in seven journal articles, nine conference publications, 13 talks presented at conferences, and training of eight graduate students. The seven journal articles were published in 2015, 2016, and 2017 and have been cited, as of March 2018, 52 times (one cited 19 times and two cited 11 times).

Sputtered p-Type CuxZn1–xS Back Contact to CdTe Solar Cells

“…Researchers over the past decades have also investigated alternate back contact materials to ZnTe:Cu, primarily Cu-containing contacts, for example, Cu x Te, − Cu x S, − Cu/HgTe, CuI, CuSCN, and Cu nanowires with graphene, with a variety of different metallization schemes. Non-Cu-containing contacts have also been explored, for example, Sb 2 Te 3 , − As 2 Te 3 , FeS 2 , MoO x , , NiO x , Ni-P, and ZnTe, but results are not definitive and efficiencies are usually lower than Cu-containing counterparts unless the absorber utilizes group V dopants. , None of these materials have yet resulted in a completely loss-free Ohmic hole-transport and electron-reflecting buffer layer, so the formation of a chemically stable barrier-free back contact without recombination remains a great challenge.…”