EFFECT OF HYDROGENATION AND THERMAL ANNEALING ON THE PHOTOLUMINESCENCE OF P-INP

The effect of hydrogenation and thermal annealing on the photoluminescence (PL) of InP:Mg and InP:Zn is presented. On hydrogenation, a rise in near-band-edge PL intensity by a factor of 16 for the InP:Mg sample and a factor of 50 for the InP:Zn sample is observed and this is attributed to the passivation of nonradiative centers. A donor-acceptor pair transition before hydrogenation in the InP:Mg sample and after hydrogenation in the InP:Zn sample was observed. In both cases, the magnitude of the shift in peak position with excitation intensity shows the involvement of a donor deeper than the normally present shallow donors. The ionization energy of the donor in InP:Mg is estimated to be 48 meV and that in InP:Zn is estimated to be <40 meV. No hydrogenation induced radiative transitions were observed. In the InP:Mg samples, the acceptor passivation effects are lost after annealing at a temperature of 350°C for 2 min, whereas the nonradiative center passivation after hydrogenation is not completely lost. In InP:Zn, the acceptor passivation along with nonradiative and deep center passivation are lost after an annealing treatment of 300°C for 2 min. A thermally induced D-A pair emission in InP:Zn which moves to lower energies with increasing annealing temperature is observed. Such a transition is not observed for InP:Mg. This can be either due to a preferential pairing of the donor and acceptor which becomes randomized after the heat treatment or due to the removal of hydrogenation effects by annealing. © 1995 American Institute of Physics.