title: Structural and compositional dependence of the CdTexSe1-x alloy layer photoactivity in CdTe-based solar cells.
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.
authors.affiliation: Center for Nanophase Materials Sciences and Department of Physics and Astronomy, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Poplawsky
authors.affiliation: Center for Nanophase Materials Sciences and Department of Physics and Astronomy, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.affiliation: Department of Physics and Astronomy, The University of Toledo, McMaster Hall, 2nd Floor Room 2017, Toledo, Ohio 43606, USA.
authors.forename: Naba
authors.initials: N
authors.lastname: Paudel
authors.affiliation: Vanderbilt University, Department of Chemistry, 7330 Stevenson Center, Nashville, Tennessee 37235, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Ng
authors.affiliation: Center for Nanophase Materials Sciences and Department of Physics and Astronomy, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA.
authors.forename: Karren
authors.initials: K
authors.lastname: More
authors.affiliation: Center for Nanophase Materials Sciences and Department of Physics and Astronomy, Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA.
authors.forename: Donovan
authors.initials: D
authors.lastname: Leonard
authors.affiliation: Department of Physics and Astronomy, The University of Toledo, McMaster Hall, 2nd Floor Room 2017, Toledo, Ohio 43606, USA.
authors.forename: Yanfa
authors.initials: Y
authors.lastname: Yan