Preparation of nonstoichiometric CuInSe2 crystals by the Bridgman method

Monocrystals of CuInSe₂ have been prepared for solar cell applications with nonstoichiometric compositions. The samples obtained with small deviation from stoichiometry were generally uniform in composition as determined by electron probe microanalysis. It was found that n-type conduction resulted only within a small compositional range, where the Se concentration was less than 50%. However, p-type materials were obtained over a wider compositional range, not only with excess of Se, but also with a deficiency of this element. X-ray diffraction showed that the samples were normally single-phase with the chalcopyrite structure and revealed no detectable shift of the diffraction peaks with variation in composition. In ingots with a large deviation from stoichiometry, localized regions of other phases were observed and examined by X-ray diffraction and electron probe microanalysis