Mass transport in CuInSe2 from first principles

The wide scatter in experimental results has not allowed drawing solid conclusions on selfdiffusion in the chalcopyrite CuInSe2 (CIS). In this work, the defect-assisted mass transport mechanisms operating in CIS are clarified using first-principles calculations. We present how the stoichiometry of the material and temperature affect the dominant diffusion mechanisms. The most mobile species in CIS is shown to be copper, whose migration proceeds either via copper vacancies or interstitials. Both of these mass-mediating agents exist in the material abundantly and face rather low migration barriers (1.09 and 0.20 eV, respectively). Depending on chemical conditions, selenium mass transport relies either solely on selenium dumbbells, which diffuse with a barrier of 0.24 eV, or also on selenium vacancies whose diffusion is hindered by a migration barrier of 2.19 eV. Surprisingly, indium plays no role in long-range mass transport in CIS; instead, indium vacancies and interstitials participate in mechanisms that promote the formation of antisites on the cation sublattice. Our results help to understand how compositional inhomogeneities arise in CIS. DOI: https://doi.org/10.1063/1.4799064 Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-81916 Accepted Version Originally published at: Oikkonen, L E; Ganchenkova, M G; Seitsonen, A P; Nieminen, R M (2013). Mass transport in CuInSe2 from first principles. Journal of Applied Physics, 113(13):133510. DOI: https://doi.org/10.1063/1.4799064 Mass transport in CuInSe2 from first principles Mass transport in CuInSe2 from first principles L.E. Oikkonen, M.G. Ganchenkova, 2 A.P. Seitsonen, and R.M. Nieminen COMP Centre of Excellence, Department of Applied Physics, Aalto University, P.O. Box 11000, FI-00076 Aalto, Espoo, Finland Department of Materials Science, National Research Nuclear University (MEPhI), 31 Kashirskoe Avenue, 115409 Moscow, Russia Physikalisch-Chemisches Institut, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich,