THE EFFECT OF THE SULFUR PRESSURE ON THE GROWTH OF CULNS2 SINGLE-CRYSTALS BY THE GRADIENT FREEZE TECHNIQUE

CuInS2 single crystals of moderate size have been produced by the gradient freeze technique under different sulfur pressures. Results from energy dispersive x-ray (EDX) microprobe analysis show that with higher sulfur pressures the cracking along the ingot decreases, but at 2 bar these cracks are still present. X-ray diffraction shows that CuS is present as a minor phase. EDX analyses along the ingot show that this phase corresponds to the cracks where In2S is released into the gas phase. Despite this loss of In2S photoluminescence reveals the bulk material to be In-rich.