Growth and Transport Properties of some Gallium Chalcogenides from the Group M2 ^III X3 ^VI Semiconductor Compounds

High quality α – Ga2 S3 single crystal were grown by a modified Bridgman method. The crystals were identified by X-ray diffraction. Measurements of electrical conductivity and Hall effect were performed in the range [ 278 – 563K] and [158 – 496K] for thermoelectric power (TEP). From these measurements the conductivity of the crystals was p-type. The electrical conductivity, Hall mobility, and hole concentration at 300K were found to be about 2.5x10^-5 Ω^-1 cm^-1 , 1.67x10^4 cm^2 v^-1 s^-1 and 9.58x10^9 cm^-3 respectively. The energy gap was found to be 1.75 eV. From the obtained experimental data several physical parameters such as diffusion coefficient, diffusion lengths, effective masses, relaxation time of carriers were estimated. In addition to these pronounced parameters, the efficiency of the thermoelectric element [figure of merit] was evaluated which leads to better application in the field of energy conversion technique.