A detailed analysis was made of radiative recombination processes, in epitaxial CuxGaySe2 layers, with the aim of investigating intrinsic defect levels as a function of chemical composition. The material was prepared by means of metalorganic vapour phase epitaxy, and temperature and excitation intensity dependent photoluminescence was used to identify various recombination mechanisms and the ionization energies of defect levels. Defect-correlated optical transitions in Cu-rich epilayers were described in terms of a recombination model which consisted of 2 acceptor and 1 donor level with ionization energies of 0.06, 0.1 and 0.012eV, respectively. The identification of a shallow compensating donor, and the attribution of the 0.1eV state to an acceptor, were the most important new aspects of this model.

Radiative Recombination via Intrinsic Defects in CuxGaySe2. A.Bauknecht, S.Siebentritt, J.Albert, M.C.Lux-Steiner: Journal of Applied Physics, 2001, 89[8], 4391-400