Comparative luminescence properties of ZnO nanorods grown on various substrates by low-temperature metalorganic chemical vapour deposition

In this study, we report on a comparative optical investigation of ZnO nanorods grown by a low-temperature metalorganic chemical vapour deposition technique on various substrates such as sapphire, silicon, GaN/sapphire, and glass. The near-band-edge excitonic features from these nanorods depend on the structural quality of ZnO. The band-edge photoluminescence (PL) decay times in these ZnO nanorods are studied by the low-temperature time-resolved PL technique. The nanorods on p-Si(1 0 0) template show comparatively longer PL decay time of 365 ps at 4.5 K, which could be due to an improved crystal quality and reduced interfacial strain. Due to the inferior crystalline quality, a slight reduction in the PL decay time has been observed in nanorods grown on glass substrate.