Photoluminescence study of alpha-irradiated MOCVD grown n-InP

The effects of alpha irradiation on n-InP grown by metal-organic chemical vapour deposition (MOCVD) have been studied using photoluminescence (PL) technique. In unirradiated n-InP, three major peaks are observed corresponding to photon energies 1.416 eV, 1.379 eV. These are identified by comparing our results with the published reports. Irradiation by 5.48 MeV alpha particles results in a pronounced decrease in the overall PL intensity, indicating the formation of non-radiative recombination centres which compete against the radiative transitions. The decrease in PL intensity is accompanied by the appearance of two new peaks corresponding to photon energies 1.392 eV and 1.311 eV. Temperature and power dependence study of these two new peaks have been carried out. The 1.392 eV peak is interpreted to be due to a transition between a shallow donor level and a new acceptor level created by the site change of an impurity due to radiation. The 1.311 eV peak is tentatively assigned to a transition between the shallow donor level and a deeper acceptor centre created by alpha irradiation. (author)