THERMOREFLECTANCE STUDY OF THE DIRECT ENERGY-GAP OF GASB

We studied the optical properties of high quality GaSb layers, grown b y molecular beam epitaxy, in the region of the fundamental gap E-0 usi ng thermoreflectance spectroscopy in the temperature range between 80 and 300 K. The experimental line-shapes were analyzed with a functiona l form model including excitonic effects. Taking advantage of the deri vative-like nature of the thermoreflectance spectroscopy, an accurate determination of the temperature dependence of the energy gap E-0(T) i s obtained, which is well reproduced by the semi-empirical Varshni rel ation. (C) 1997 Elsevier Science Ltd.