Absorption and Photoluminescence Spectra of Heavily Zn-Doped CuGaS_2 Crystals

概要

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In heavily Zn-doped (up to 5 %) CuGaS_2 crystals, reductions of excitonic absorption and above-band-gap absorption were observed for optical transitions of the polarization parallel to the optic axis, probably related to a change in the exciton oscillator strength ratio of the transitions of polarizations parallel and perpendicular to the optic axis. An impurity absorption whose concentration dependence is consistent with electron transitions from Zn_<Ga> acceptors to the conduction band is reported for the first time. An emission appearing at 2.1〜2.3 eV is considered to be due to the electron transitions from a donor level of sulfur vacancies or their complexes with Zn_<Ga> to the Zn_<Ga> acceptor level, involving the effect of broadening of the latter level. The existence of isoelectronic-trap Zn_<Cu>Zn_<Ga> pairs is suspected from time-resolved emission spectra.
社団法人応用物理学会の論文
1991-11-15