Defect physics of the CuInSe{sub 2} chalcopyrite semiconductor
- National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)
- The Institute of Scientific and Industrial Research, Osaka University, Osaka 567 (Japan)
We studied the defect physics in CuInSe{sub 2}, a prototype chalcopyrite semiconductor. We showed that (i) it takes much less energy to form a Cu vacancy in CuInSe{sub 2} than to form cation vacancies in II-VI compounds (ii) defect formation energies vary considerably both with the Fermi energy and with the chemical potential of the atomic species, and (iii) the defect pairs such as (2V{sub Cu}{sup {minus}}+In{sub Cu}{sup 2+}) and (2Cu{sub In}{sup 2{minus}}+In{sub Cu}{sup 2+}) have particularly low formation energies (under certain conditions, even exothermic). Using (i){endash}(iii), we (a) explain the existence of unusual ordered compounds CuIn{sub 5}Se{sub 8}, CuIn{sub 3}Se{sub 5}, Cu{sub 2}In{sub 4}Se{sub 7}, and Cu{sub 3}In{sub 5}Se{sub 9} as a repeat of a single unit of (2V{sub Cu}{sup {minus}}+In{sub Cu}{sup 2+}) pairs for each n=4, 5, 7, and 9 units, respectively, of CuInSe{sub 2}; (b) attribute the very efficient p-type self-doping ability of CuInSe{sub 2} to the exceptionally low formation energy of the shallow defect Cu vacancies; (c) explained in terms of an electronic passivation of the In{sub Cu}{sup 2+} by 2V{sub Cu}{sup {minus}} the electrically benign character of the large defect population in CuInSe{sub 2}. Our calculation leads to a set of new assignment of the observed defect transition energy levels in the band gap. The calculated level positions agree rather well with available experimental data. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 600989
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 57, Issue 16; Other Information: PBD: Apr 1998
- Country of Publication:
- United States
- Language:
- English
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