Bridgman growth of CuGa/sub x/In/sub 1-x/Se/sub 2/

Using a vertical Bridgman method, ingots with the melt composition CuGa/sub x/In/sub 1-x/Se/sub 2/ were grown with x = 0.2 and 0.3. These quaternary materials were confirmed, by X-ray diffraction and observed cleavage plane angles, to be single phase chalcopyrite, despite a reported copper deficiency in stoichiometrically prepared ingots. All were p-type but more brittle than ternary ingots (x = O), prepared in a similar way. The lattice a-spacings decreased with gallium content from x = 0 to 0.3, as expected, as did the long wavelength quantum efficiency edge values in photovoltaic cells fabricated from the ingots. In one of these cells, Mott-Schottky, dark current-voltage and photocurrent-capacitance measurements were made. Some transport measurements were also carried out on filaments cut from the ingots.