Wurtzite InP nanowires (NWs), transferred onto various substrates, were investigated by low temperature micro-photoluminescence. A clear PL emission shift, depending on the substrate, is observed and attributed to the substrate-induced strain, generated due to the difference in the thermal expansion coefficients of the InP NWs and the host-substrate during the sample cooling. Moreover, a blueshift of the PL emission peak is observed as the excitation power is increased. This effect, which is not observed on the as-grown sample, is thus a consequence of the host substrate and not an intrinsic property of the nanowires.
Applied Physics Letters 101, 072101 (2012)