title: Atomic and electronic structure of Lomer dislocations at CdTe bicrystal interface.
abstract: Extended defects are of considerable importance in determining the electronic properties of semiconductors, especially in photovoltaics (PVs), due to their effects on electron-hole recombination. We employ model systems to study the effects of dislocations in CdTe by constructing grain boundaries using wafer bonding. Atomic-resolution scanning transmission electron microscopy (STEM) of a [1-10]/(110) 4.8° tilt grain boundary reveals that the interface is composed of three distinct types of Lomer dislocations. Geometrical phase analysis is used to map strain fields, while STEM and density functional theory (DFT) modeling determine the atomic structure at the interface. The electronic structure of the dislocation cores calculated using DFT shows significant mid-gap states and different charge-channeling tendencies. Cl-doping is shown to reduce the midgap states, while maintaining the charge separation effects. This report offers novel avenues for exploring grain boundary effects in CdTe-based solar cells by fabricating controlled bicrystal interfaces and systematic atomic-scale analysis.
authors.affiliation: Department of Materials Science and Engineering, the University of Texas at Dallas, Richardson, TX 75080, USA.
authors.forename: Ce
authors.initials: C
authors.lastname: Sun
authors.affiliation: Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA.
authors.forename: Tadas
authors.initials: T
authors.lastname: Paulauskas
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL 60439, USA.
authors.forename: Fatih G
authors.initials: FG
authors.lastname: Sen
authors.affiliation: Department of Materials Science and Engineering, the University of Texas at Dallas, Richardson, TX 75080, USA.
authors.forename: Guoda
authors.initials: G
authors.lastname: Lian
authors.affiliation: Department of Materials Science and Engineering, the University of Texas at Dallas, Richardson, TX 75080, USA.
authors.forename: Jinguo
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Buurma
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL 60439, USA.
authors.forename: Maria K Y
authors.initials: MK
authors.lastname: Chan
authors.affiliation: Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Klie
authors.affiliation: Department of Materials Science and Engineering, the University of Texas at Dallas, Richardson, TX 75080, USA.
authors.forename: Moon J
authors.initials: MJ
authors.lastname: Kim