Structural and compositional dependence of the CdTexSe1-x alloy layer photoactivity in CdTe-based solar cells

Jonathan D Poplawsky; Wei Guo; Naba Paudel; Amy Ng; Karren More; Donovan Leonard; Yanfa Yan

doi:10.1038/ncomms12537

Structural and compositional dependence of the CdTexSe1-x alloy layer photoactivity in CdTe-based solar cells

Nat Commun. 2016 Jul 27:7:12537. doi: 10.1038/ncomms12537.

Authors

Jonathan D Poplawsky¹, Wei Guo¹, Naba Paudel², Amy Ng³, Karren More¹, Donovan Leonard¹, Yanfa Yan²

Affiliations

¹ Center for Nanophase Materials Sciences and Department of Physics and Astronomy, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA.
² Department of Physics and Astronomy, The University of Toledo, McMaster Hall, 2nd Floor Room 2017, Toledo, Ohio 43606, USA.
³ Vanderbilt University, Department of Chemistry, 7330 Stevenson Center, Nashville, Tennessee 37235, USA.

Abstract

The published external quantum efficiency data of the world-record CdTe solar cell suggests that the device uses bandgap engineering, most likely with a CdTexSe1-x alloy layer to increase the short-circuit current and overall device efficiency. Here atom probe tomography, transmission electron microscopy and electron beam-induced current are used to clarify the dependence of Se content on the photoactive properties of CdTexSe1-x alloy layers in bandgap-graded CdTe solar cells. Four solar cells were prepared with 50, 100, 200 and 400 nm-thick CdSe layers to reveal the formation, growth, composition, structure and photoactivity of the CdTexSe1-x alloy with respect to the degree of Se diffusion. The results show that the CdTexSe1-x layer photoactivity is highly dependent on the crystalline structure of the alloy (zincblende versus wurtzite), which is also dependent on the Se and Te concentrations.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't