Temperature dependence of the whispering gallery effect in ZnO nanoresonators

摘要

We have investigated the optical modes of zinc oxide (ZnO) nanostructures with hexagonal cross section by temperature-dependent cathodoluminescence spectroscopy. All observed resonance lines show a characteristic red-shift with increasing resonator temperature. From such red-shift we calculate the temperature dependence of the refractive indices of individual ZnO nanopillars on the basis of numerical solutions for the resonant photon energies of hexagonal whispering gallery modes using literature values for the thermal expansion coefficient of ZnO.