BLUE EMISSION AND BANDGAP MODIFICATION IN N:ZnO NANORODS

Abstract

Nanorods of nitrogen-doped ZnO (N:ZnO) are grown by hydrothermal chemical precipitation method. The average crystallite size, surface morphology, and particle size distribution are estimated and characterized from powder X-ray diffractometer (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), respectively. The characteristic vibration mode of metal-oxide is confirmed from Fourier transform infrared spectroscopy (FT-IR) study. The absorption spectra of N:ZnO in the ultraviolet visible (UV-vis) region and their variations are recorded as a function of dopant concentration. The Tauc plot elucidates that the bandgap of N:ZnO increases up to 6 atomic percent (at.%) of dopant concentration and then decreases for heavy doping. The widening and narrowing in bandgap is interpreted in terms of impurity induced absorption edge shift due to N doping. Photoluminescence (PL) spectra revealed the existence of visible band, arising from impurity related defects.