Siepchen, B.B.SiepchenSpäth, B.B.SpäthDrost, C.C.DrostKrishnakumar, V.V.KrishnakumarKraft, C.C.KraftWinkler, M.M.WinklerKönig, J.D.J.D.KönigBartholome, K.K.BartholomePeng, S.S.Peng2022-03-052022-03-052015https://publica.fraunhofer.de/handle/publica/24081010.1007/s11664-015-3894-2CdTe solar technology has proved to be a cost-efficient solution for energy production. Formation of the back contact is an important and critical step in preparing high-efficiency, stable CdTe solar cells. In this paper we report a simple CdTe solar cell (Sb<inf>2</inf>Te<inf>3</inf>) back contact-formation process. The CdS and CdTe layers were deposited by close-space sublimation. After CdCl<inf>2</inf> annealing treatment, the CdTe surface was etched by use of a mixture of nitric and phosphoric acids to obtain a Te-rich surface. Elemental Sb was sputtered on the etched surface and successive post-annealing treatment induced Sb<inf>2</inf>Te<inf>3</inf> alloy formation. Structural characterization by x-ray diffraction analysis confirmed formation of the Sb<inf>2</inf>Te<inf>3</inf> phase. The performance of solar cells with nanoalloyed Sb<inf>2</inf>Te<inf>3</inf> back contacts was comparable with that of reference solar cells prepared with sputtered Sb<inf>2</inf>Te< inf>3</inf> back contact from a compound sputter target.en621journal article