Temperature and excitation dependent lasing characteristics of ZnO nanorods

Band edge related excitonic lasing has been observed in ZnO nanorods grown by chemical vapor deposition technique on sapphire substrate without using any catalyst. The nanorods were optically pumped using a 325 nm laser source and the emission characteristics were studied in detail by varying temperature and excitation intensity. The nanorods showed the onset of lasing characteristics below 150 K which became prominent at 3.4 K with sharp multimodal emission characteristics. The threshold pump power for the onset of lasing was found to be 14.5 mW at 3.4 K.