Determination of Fe(sup 2+) and Fe(sup 3+) concentrations of semi- insulating InP:Fe

摘要

Semi-insulating InP is most commonly obtained by doping with the deep acceptor iron to compensate the shallow donors which otherwise render the material n-type conducting. As the Fermi level in semi-insulating InP is closed to the iron acceptor level, both charge states - Fe(sup 2+) as well as Fe(sup 3+) corresponding to the acceptor level occupied unoccupied by an electron - are present. Mayor et al.(1) presented a method based on absorption measurements in the nearbandgap region of InP to determine the concentration of both charge states separately. In this paper we compare iron concentrations obtained by this method with the results from intracenter absorption, DLTS, EPR, Hall effect measurements and glow discharge mass spectroscopy. We present a new calibration for the optical absorption cross sections.