Single crystal growth of Ga2(SexTe1−x)3Ga2(SexTe1−x)3 semiconductors and defect studies via positron annihilation spectroscopy

Small single crystals of Ga2(SexTe1−x)3Ga2(SexTe1−x)3 semiconductors, for x  =0.1, 0.2, 0.3, were obtained via modified Bridgman growth techniques. High resolution powder x-ray diffractometry confirms a zincblende cubic structure, with additional satellite peaks observed near the (111) Bragg line. This suggests the presence of ordered vacancy planes along the [111] direction that have been previously observed in Ga2Te3Ga2Te3. Defect studies via positron annihilation spectroscopy show an average positron lifetime of ≈400ps in bulk as-grown specimens. Such a large lifetime suggests that the positron annihilation sites in these materials are dominated by defects. Moreover, analyzing the electron momenta via coincidence Doppler broadening measurements suggests a strong presence of large open-volume defects, likely to be vacancy clusters or voids.

► Ga2(SexTe1−x)3Ga2(SexTe1−x)3 growth via modified Bridgman methods.
► High-resolution x-ray powder diffractometry on Ga2(SexTe1−x)3Ga2(SexTe1−x)3.
► Positron annihilation spectroscopy on Ga2(SexTe1−x)3Ga2(SexTe1−x)3.