Chemical vapor transport of chalcopyrite semiconductors: CuGaS2 and AgGaS2 ☆

摘要: Abstract Crystals of CuGaS2 and AgGaS2 with different isotopic compositions have been grown by chemical vapor transport (CVT) using iodine as the agent. Before performing CVT growth, sulfur copper were purified sublimation etching, respectively. 109Ag etched 71Ga isotopes from oxides vacuum annealing. Transparent yellow orange crystals greenish obtained in shape platelets, chunks, rods needles sizes up to 8 mm (CuGaS2) 30 mm (AgGaS2). These used study their electronic, vibrational thermodynamic properties. Higher excitonic states (n=2,3) observed at low temperatures wavelength-modulated reflectivity spectroscopy, thus proving an excellent surface crystal quality. In addition, experimentally determined non-monotonic temperature dependence energies can be well fitted two Bose–Einstein oscillators statistical factors, corresponding characteristic acoustic optical phonon frequencies. Isotopic shift has also successfully these crystals.