Solar Energy Materials and Solar Cells, Vol.75, No.1-2, 135-143, 2003
Study of point defects in CuGaSe2 single crystals by means of electron paramagnetic resonance and photoluminescence
Point defects in CuGaSe2 single crystals as vacancies V-Se, V-Cu and defect pair (2V(Cu)(-) + Ga-Cu(2+)) have been studied by means of electron paramagnetic resonance (EPR) and low-temperature photoluminescence (PL). EPR hyperfine structure has been found at temperatures as low as 1.45-45 K and the temperature dependence of EPR line is discussed. Photo-EPR spectrum reveals optically active behavior of intrinsic point defects in CuGaSe2 crystals. Three bands of PL emission show different origins and two low-energy bands at 1.55 and 1.58 eV have been found to be steady despite H-2-, O-2- and Se-2-annealings. The experimental data added with electric characterization in accordance with the used annealings and together with a defect physics model allow consideration of the point defect ensemble in CuGaSe2 in more detail. (C) 2002 Elsevier Science B.V. All rights reserved.
Keywords:chalcopyrite crystals;electron paramagnetic resonance (EPR);photo-EPR;Photoluminescence (PL);point defects and defect pairs