PREPARATION AND PROPERTIES OF COPPER GALLIUM DISELENIDE.

Copper Gallium Diselenide (CuGASe//2) is one of the comparatively less studied I-III-VI//2 chalcopyrite semiconductors. Single crystals of CuGaSe//2 were grown from the elements by the Bridgeman method. Electrical conductivity and thermoelectric power as a function of temperature were studied on rectangular pieces of these samples. The room temperature conductivity was 0. 128 mhos/cm. This yielded that there are 4 multiplied by 10**2**2 per cm**3 holes (mobility is taken as 20 cm**2/volt/sec) due to intrinsic defects (either copper vacancies or selenium interstitials). The two acceptor activation energies were 0. 37 and 0. 77 eV in the low and high temperature regions between 300 degree to 500 degree K. Thermoelectric power data indicated that it is composed of two contributions one a straight line with 1/T and the other a curve. The optical absorption data on thin films evaporated by resistive heating gave a fundamental edge at 1. 48 eV.