Growth of Cu2GeS3 bulk single crystals by chemical vapor transport with iodine

Abstract Bulk crystals of Cu 2 GeS 3 , a candidate material for thin-film solar cells, were grown using chemical vapor transport with two different iodine concentrations. X-ray diffraction (XRD) suggested that both samples consisted only of Cu 2 GeS 3 crystals. Raman spectra varied from crystal to crystal, which may be due to different preferential orientations, as suggested from the XRD patterns of the flaky crystals. Selected area electron diffraction patterns showed a regular array of spots consistent with monoclinic Cu 2 GeS 3 , which suggests that the samples were monocrystalline Cu 2 GeS 3 with a monoclinic structure.