ESR and PL Characterization of CuGaSe2 Single Crystals

T. Nishi, Y. Katsumata, K.Sato and H. Miyake*

Tokyo University of Agriculture &Technology, *Mie University
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Proc. PVSEC11, Sapporo, Sep. 1999, Solar Energy Materials and Solar Cells (2000) to be published

Electron spin resonance (ESR) and Photoluminescence (PL) spectra of CuGaSe2 single crystals were measured to elucidate defect properties in this compound. A narrow isotropic ESR line with the bandwidth of 0.9 mT and the g-value of 2.006 was observed at 4 K. The intensity of the signal increased by an H2-annealing and decreased by an O2 annealing, from which the signal was assigned to that of an electron trapped by the Se-Vacancy (VSe). A PL signal due to VSe was observed, which disappeared by the O2-annealing. Both ESR and PL measurements suggest the presence of a VSe defect in the CuGaSe2 single crystals. Another unidentified signal was observed in ESR spectrum and was associated with a Fe-center, taking into account the strong angular dependence of the signal. Keyword: electron spin resonance (ESR), photoluminescence (PL), Se-vacancy, annealing, CuGaSe2 ;