Revisiting the defect physics in CuInSe{sub 2} and CuGaSe{sub 2}
- National Renewable Energy Lab., Golden, CO (United States)
Using first-principles self-consistent electronic structure theory, the authors have calculated defect formation energies and defect energy levels in CuInSe{sub 2}. Contrary to previously accepted assumptions in the analysis of defects in CuInSe{sub 2} they find that (i) it is much easier to form Cu vacancy in CuInSe{sub 2} than to form cation vacancies in II-VI`s; (ii) defect formation energies vary considerably both with the Fermi energy and the chemical potential of the atomic species, and (iii) defect pairs such as (2V{sub Cu} + Inc{sub Cu}) have a remarkably low formation enthalpy. This explains the massive non-stoichiometry of CuInSe{sub 2} and the appearance of ordered defect 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}. The fact that CuInSe{sub 2} has good electrical properties despite this off-stoichiometry reflects the mutual passivation of In{sub Cu} by V{sub Cu}. Similar results are found for CuGaSe{sub 2}, except that (iv) it is more difficult to form (2V{sub Cu}{sup {minus}} + Ga{sub Cu}{sup 2+}) in CuGaSe{sub 2} than to from (2V{sub Cu}{sup {minus}} + In{sub Cu}{sup 2+}) in CuInSe{sub 2}, and (v) the Ga{sub Cu} donor levels are much deeper than the In{sub Cu} donor levels. Thus, it is more difficult to dope CuGaSe{sub 2} n-type.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 302495
- Report Number(s):
- CONF-970953-; TRN: IM9904%%283
- Resource Relation:
- Conference: 26. IEEE photovoltaic specialists conference, Anaheim, CA (United States), 29 Sep - 3 Oct 1997; Other Information: PBD: 1997; Related Information: Is Part Of Conference record of the twenty sixth IEEE photovoltaic specialists conference -- 1997; PB: 1477 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effects of Na on the electrical and structural properties of CuInSe{sub 2}
Effects of Ga addition to CuInSe{sub 2} on its electronic, structural, and defect properties