Excitation and temperature dependence of the excitonic emissions in undoped and Mg-doped VPE InP

The photoluminescence of vapor phase epitaxial indium phosphide, both unimplanted and magnesium implanted, is investigated as a function of excitation intensity and temperature to gain a more complete understanding of the free exciton, exciton-bound donor, exciton-bound acceptor (residual and Mg), the 1.4155 eV emission identified with both the recombination of free holes with neutral donors and with bound excitons to ionized donors, and the recently identified 1.4122 eV emission (unique to Mg implanted layers). Emission peak broadening, quenching, and saturation is examined as the irradiance is varied from 0.002 to 33.3 W/cm² and the temperature from 2.6 to 50 K. The source of the 1.4122 eV emission is speculated to be a donor-acceptor recombination involving a donor center bond to an off-axis band and the Mg acceptor, or more likely, excitons bound to point defects which are created by the acceptor implant.