Swift heavy ion irradiated InGaAs/InP multi quantum wells: Band-structure, interface and surface modifications

The band-structure, interface and surface modification by swift heavy ion irradiation of In0.55Ga0.45As/InP multi quantum wells have been studied using photoluminescence, high resolution X-ray diffraction and atomic force microscopy. Three distinct photoluminescence peaks were observed for as-grown samples at low temperature and at room temperature the peaks merge together. Detailed analysis has been carried out to understand the origin of additional satellite peaks. A peak shift of about 23 nm was observed for irradiated samples after annealing. Highly-ordered satellite peaks were observed in X-ray scans of as-grown and Ag ion irradiated samples. In comparison, Au ion irradiated sample showed stronger interfacial degradation as seen by the diminished satellite peaks. The peak position of the irradiated samples shifted to the compressive side and was broadened in comparison with as-grown samples. The as-grown and annealed samples show smooth surfaces whereas irradiation results in nano-sized dot/island types of structures at the surface. The results are discussed in the light of complementary information provided by these techniques.