The optical setup based on the double grating monochromator equipped with fiber coupled LEDs and the photomultiplier has been optimized for the photoluminescence spectroscopy of the highly scattering thin films in the spectral range 300−750 nm. The photoluminescence study has been applied on the hydrogen and oxygen plasma treated, nominally undoped (intrinsic) ZnO aligned nanocolumns grown by hydrothermal process. Water wettability study revealed that the hydrogenated ZnO nanocolumns are highly hydrophobic with surface contact angle about 100° decreasing below 20° after the plasma oxidation (hydrophilic surface). Photoluminescence spectroscopy showed that after plasma hydrogenation, the exciton related emission band centered at the wavelength 375 nm was partly deteriorated but fully recovered after the subsequent plasma oxidation. Therefore, the exciton related photoluminescence is influenced significantly by the plasma treatment and it correlates with free electron concentration.Keywords: ZnO; nanocolumns; hydrothermal growth; Photoluminescence spectroscopy; contact angle
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