Micro-Raman and photoluminescence spectroscopies of horizontal Bridgman-grown AgGaSe2 -: art. no. 093523

AgGaSe2 crystals grown by the horizontal Bridgman technique were studied by room-temperature micro-Raman scattering and low-temperature photoluminescence (PL) spectroscopies. The most intense Raman line observed had the frequency of 177 cm(-1), corresponding to the Gamma(1)(W-1) mode. The measurements were performed along the direction of growth of the boule and the line frequency was found to be almost constant within the experimental accuracy. The average full width at half maximum of the Gamma(1)(W-1) mode was found to be 4.6 cm(-1) and its insignificant variation along the ingot suggests its structural and compositional uniformities. At low temperature (8 K), the main PL peak at 1.772 eV is due to donor-acceptor-pair recombination. A doublet in the excitonic peak, observed at that temperature, suggests a reduced inhomogeneous broadening and the better crystallinity of the sample, when compared with the previous literature. The dispersion of the various PL peaks along the length of the ingot was also found negligible, which indicates the compositional homogeneity and the uniform distribution of the intrinsic defects. (c) 2005 American Institute of Physics.