Ion channeling study of defects in CuInTe₂ single crystals

Abstract

Ion channeling spectra of as-grown CuInTe, single crystals are measured using a 2 MeV 4He' analysing beam. It is found that the measured minimum yields cannot be explained within a model of randomly distributed non-interacting point defects caused by deviations from ideal stoichiometry. A model with extended defects due to vacancy clustering and dislocation formation is proposed to interprete the experimental results.

Photoacoustic Spectroscopy of Defect States in Etched and Air‐annealed CuInSe2 Single Crystals

“…The origin of this feature observed already in some previous studies (YAKUSHEV et al 1994a, b, d) is not yet understood. Formation of a thin selenium layer on the crystal surface, formation of selenium interstitials and incorporation of selenium atoms into empty cation sites (most likely copper sites) have been discussed as possible mechanisms to explain the selenium peak in the channeling spectra of polished and etched CuInSe, single crystals ( YAKUSHEV et al 1994aYAKUSHEV et al , 1995. Although it is rather likely that the selenium peak in the channeling spectra is in some way related to the observation of lower valent selenium at the surface of etched CuInSe, crystals (CAHEN et al) the latter effect does not help us to construct a consistent model to explain all the experimental findings.…”

“…In previous considerations of the intrinsic defect chemistry in CuInSe, it has been often argued that the formation of selenium interstitials is rather unlikely because of their high formation enthalpy (NEUMAANN 1986), but to understand the results of recent ion channeling studies on CuInSe, single crystals subjected to various treatments ( YAKUSHEV et al 1994a, b, d) including polishing and etching (Fig. 6) it was necessary to revise this point of view and to admit that selenium interstitials can exist in CuInSe,, may be as metastable defects (YAKUSHEV et al 1995). Finally, some remarks concerning the possible nature of the donor with an ionisation energy of 115 meV which has been previously ascribed to selenium vacancies (ABOU- ELFOTOUH et al 1987ELFOTOUH et al , 1991.…”