Photo hall measurements of band-tail absorption and recombination times in indium antimonide

Photo Hall measurements are reported for a n-type InSb sample at 77 K. A bulk recombination time of 350 ns and an effective surface recombination time of 20 ns, corresponding to a surface recombination velocity of 2.8 X 10⁵ cm s^-1, has been estimated from analysis of the frequency dependence of the photocarrier generation. The measurements yield interband absorption coefficients in the band-tail which are systematically lower than the previous optical measurements, being up to an order of magnitude lower at 100 cm^-1 below the band edge. The form of the band-tail is qualitatively described in terms of the convolution of an exponential edge and an acceptor impurity resonance. © 1987.