Optical properties of ZnO microrods grown by a hydrothermal method – a cathodoluminescence study

Abstract

Optical properties of individual zinc oxide microrods grown by a microwave-assisted hydrothermal method are investigated by spatially and spectrally resolved cathodoluminescence spectroscopy and imaging at liquid-helium temperature. For optimized growth conditions the strong localization of cathodoluminescence emission at the corners of the individual hexagonal ZnO microrods has been revealed. Locally distributed luminescence and fine structure of near-band-edge emission are discussed as a manifestation of whispering gallery modes of the hexagonal resonator occurring for the near band-gap luminescence in the investigated microrods.