Abstract

An investigation of the photogeneration of carriers via interband transitions has yielded new data for the linear absorption band tail and the nonlinear refraction in InSb. The measurements are based on a photo-Hall technique [1] which permits direct assessment of the photogenerated carrier population. Optical absorption coefficients as low as 0.01 cm^-1 may be observed by this technique. The new measurement of the InSb band tail at a temperature of 77 K is shown in Fig. 1 and, from the associated theoretical fit, the form of the curve may be accurately interpreted as a spectral Urbach tail convoluted with an absorption feature from acceptor impurities [2].

© 1988 Optical Society of America