Dependence of Conduction Type of Solid State Grown Cu-In-Se Compounds on Composition Around CuIn3Se5

We have succeeded to prepare Cu-ln-Se bulk crystals by solid state growth method with Cu2Se and In2Se3 as raw materials. In/(Cu+In) ratios of them were around CuIn3Se5 and Cu2ln4Se7, which are expected as key materials in a system of CuInSe2 based solar cells. Most of x-ray diffraction patterns of samples were very close to each other. Resistivities were as large as 10⁸ Ω ·cm. Both conduction types, p and n, were confirmed. There was an obvious border in In/(Cu+In) in conduction types at In/(Cu+In) 0.75, corresponding to CuIn3Se5.