Hydrogen indium vacancy complex VInH 4 in n-type InP studied by positron-lifetime

Abstract

Positron-lifetime experiments have been carried out on two undoped n-type liquid encapsulated Czochralski (LEC)-grown InP samples with different stoichiometric compositions in the temperature range 10–300 K. For temperatures below 120 K for P-rich InP and 100 K for In-rich InP, the positron average lifetime began to increase rapidly and then leveled off, which was associated with the charge state change of hydrogen indium vacancy complexes from ( V InH 4) + to ( V InH 4) 0. This phenomenon was more obvious in P-rich samples that have a higher concentration of V InH 4. The transformation temperature of approximately 120 K suggests that the complex V InH 4 is a donor defect and that the ionization energy is about 0.01 eV. The ionization of neutral V InH 4 accounted for the decrease of the positron average lifetime when the sample was illuminated with a photon energy of 1.32 eV at 70 K. These results provide evidence for hydrogen complex defects in undoped LEC InP.