On the structured imperfections of bulk GaSb using high resolution transmission electron microscopy

GaSb is a promising III-V direct band gap semiconductor with sphalerite type FCC structure. Its band gap value has made it an excellent candidate for the conversion of infrared radiation to electricity. The wafers of GaSb, that were studied, originated from ingots grown with the Liquid Encapsulated Chochralski method. In all cases, Energy Dispersive X-ray Spectroscopy and Particle Induced X-ray Emission measurements demonstrated an excess of Sb. In the present work conventional transmission electron microscopy (CTEM) and high resolution electron microscopy (HRTEM) were used in order to determine the effect of the Sb excess in the structural characteristics of the material, mainly after thermal treatment. A structure model based on the ordering of the Sb antisites (SbGa) rather than the Ga vacancies (VGa) is proposed for the observed modulation in small areas of the material.