Effect of nitrogen doping on structural and optical properties of ZnO nanoparticles

Influence of nitrogen doping on structural and optical properties of ZnO nanoparticles has been studied. Undoped and N doped ZnO nanoparticles were synthesized via chemical precipitation approach. The prepared samples were characterized through X-ray diffraction (XRD), Transmission electron microscopy (TEM) equipped with Energy dispersive X-ray (EDAX) spectroscopy, UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and micro-Raman spectroscopy (µRS). Wurtzite phase of undoped as well as 0.5-10% N doped ZnO nanoparticles was confirmed through characteristic XRD patterns. The particle size expansion due to N incorporation in ZnO was further revealed by TEM and EDAX analysis where 11 nm size undoped and 18-22 nm size 0.5-10% N doped ZnO (N:ZnO) nanoparticles without any impurity were ascertained. Slight blue-shift in band gap energy, as observed in our case, symbolized weak quantum confinement of the prepared nanoparticles. The alterations in vibrational modes of ZnO due to N incorporation, remarkably H substituting at O site and subsequently causing the passivation in N:ZnO nanoparticles, were detected through FTIR analysis. Finally, the effect of the nano-size of crystallite and gradual prominence of N into ZnO lattice due to increase of N doping concentration in prepared nanoparticles was meticulously expatiated though µRS analysis.