Growth of Ga_xIn_(1-x)Sb bulk crystals for infrared device applications by vertical Bridgman technique

摘要

Good quality Ga_xIn_(1-x)Sb bulk crystals, suitable for infrared (IR) device applications, were successfully grown by using vertical Bridgman technique. A number of experiments were carried out with different ampoule lowering rate, axial temperature gradient and ampoule cone angle in order to optimize the growth conditions. For checking the chemical homogeneity, the grown crystals were subjected to X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis. The formation and growth of the crystals was confirmed by the XRD analysis. Chemical etching revealed no observable variation of defect-density distribution. Electrical and optical absorption studies of the grown crystals were also studied. IR transmittance studies revealed the sharp cutoff at shorter wavelength and high-percentage transmittance, which are the essential conditions for the infrared device applications.