Single crystal growth of Cu(Ga,In)Se2 solid solutions by horizontal Bridgman method with controlling Se vapor pressure and their defect properties

Abstract The analysis of chemical reactions shows that In-rich Cu(Ga,In)Se 2 bulk crystals can be grown using the horizontal Bridgman method from melts. We have grown the In-rich solid solutions using the above-mentioned method with controlling Se vapor pressure from 20 to 500 Torr, based on temperature dependence of the Cu(Ga,In)Se 2 phase diagram. These products are shown to have a single chalcopyrite phase by X-ray diffraction. The bulk single crystals with good crystalline quality can be grown under Se vapor pressure from 80 to 250 Torr. The electrical and optical properties of the intrinsic defects have been investigated by annealing samples in vacuum and Se-atmosphere. Acceptors having activation energies of about 20, 35 and 140 meV are presumably ascribed to Cu-vacancies, Cu in the III site, and III-vacancies, respectively. Donors having activation energies of about 35 and 70–80 meV are ascribed to two different kinds of Se-vacancies.