Optical Characterization of ZnO Nanorods Grown by the Ultra-Fast and Low Temperature Hydrothermal Process

The results of photoluminescence investigations of zinc oxide nanorods are reported. These nanorods grown on undoped silicon substrates were obtained by low temperature and ultra-fast version of a microwave-assisted hydrothermal method. The photoluminescence investigations show very high quality of the obtained material. From photoluminescence studies we conclude the lack of carrier localization effects. The photoluminescence is dominated by band gap edge emission of bound excitonic (donor bound excitons) origin. Thus, the photoluminescence quenching observed at increased temperatures is associated with thermal ionization of shallow donors. From photoluminescence analysis (changes of photoluminescence line width) a strength of exciton-acoustic phonon coupling is evaluated.