Optical absorption tail in InP:Mn from surface photovoltage measurements

The steady-state surface photovoltage technique was used to determine the optical absorption tail of InP:Mn, by extrapolation from the above-band-gap absorption spectrum. Reabsorbed recombination radiation is shown to have no effect on this procedure although it does raise the effective minority-carrier diffusion length. The tail absorption coefficient of InP:Mn increases with hole density in the range of 4.1×1014 cm to 5.3×1016 cm−3. In the 1016 cm−3 range, the absorption coefficient appears to rise also with the density of dislocations.