Defect-induced Nonpolar-to-polar Transition at the Surface of CuInSe2
In contrast to zinc-blende semiconductors, where the nonpolar (110) surface has the lowest energy, our first-principles calculations on the chalcopyrite semiconductor CuInSe2 reveal that facets terminated by the (112)-cation and -Se polar surfaces are lower in energy than the unfaceted (110) plane, despite the resulting increased surface area. This explains the hitherto puzzling existence of polar microfacets on nominally nonpolar (110) chalcopyrite surfaces. The extraordinary stability of these polar facets originates from the effective neutralization of surface charge by low-energy ordered CuIn antisite or Cu vacancy surface defects, while the relaxed but defect-free (112) surface is metallic and much higher in energy. We explain the low carrier density of the observed faceted surface in terms of autocompensation between opposite-polarity facets.
- Research Organization:
- Pacific Northwest National Lab., Richland, WA (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 15007685
- Report Number(s):
- PNNL-SA-38658; JPCSAW; TRN: US200419%%444
- Journal Information:
- Journal of Physics and Chemistry of Solids, Vol. 64, Issue 9-10; Other Information: PBD: 10 Sep 2003; ISSN 0022-3697
- Country of Publication:
- United States
- Language:
- English
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