Growth of III2VI3 compound semiconductor (GaxIn1−x)2Se3 single crystals with giant optical activity for visible and infrared light

Abstract

High grade single crystals of $({\mathrm{Ga}}_x{\mathrm{In}}_{\text{1−x}}{)}_2{\mathrm{Se}}_3$ showing giant optical activity for visible and infrared light have been successfully grown with an iodine transport technique. Two kinds of single crystals with reverse rotatory directions to each other have been obtained; one is the dextrorotatory with space group ${\text{P6}}_1$ and another is the levorotatory with ${\text{P6}}_5.$ The composition x is controlled from 0.03 to 0.70. The morphology is hexagonal plate and the size is up to 3 mm in diameter and hundreds of microns in thickness. The crystals for different compositions x possess different fundamental optical absorption edges from 610 to 720 nm. The crystal habit facets are the (001) and {110} planes. These crystals have a polarity and their growth direction is limited to the [00-1] direction. The lattice defects such as antiphase domain boundary, stacking fault, inversion twin, and reversion screw almost have not been observed. It is found that these growth characteristics are strongly related to the crystal structure in which the structural vacancies are ordered in screw form along the c axis.