Electron Paramagnetic Resonance and Photoluminescence Study of Defects in CuGaSe₂Single Crystals Grown by the Traveling Heater Method

Abstract

Electron paramagnetic resonance (EPR) at T = 4.2 K and photoluminescence (PL) spectra at T = 20 K have been employed to elucidate point defect features in CuGaSe 2 crystals grown by the traveling heater method. Isotropic and anisotropic paramagnetic centers have been found in crystals as-grown and annealed in various gas mediums. Three PL bands have been observed and the influence of H 2 , O 2 and Se 2 annealing has been studied. The presence of donor singlet V Se + has been evidenced in as-grown and H 2 annealed crystals. Complex study of EPR, PL spectra and defect physics models have allowed the addition of the point defect ensemble in CuGaSe 2 with defect pairs (2V Cu - + Ga Cu 2+ ), V Cu and other defect complexes, according to treatments used in this work.