Vibrational spectroscopy of undoped and nitrogen-doped ZnO grown by metalorganic chemical vapor deposition

Raman backscattering and Fourier transform infrared measurements were performed on undoped and nitrogen-doped ZnO. Two broad vibrational modes near 1414 and 1585cm−1 were found that are attributed to the presence of carbon sp2 clusters. In nitrogen-doped ZnO these modes are enhanced. In addition a broad vibrational mode near 2004cm−1 is believed to be due to Zn–H complexes. The incorporation of N results in the formation of cyano radicals NO and NNO complexes effectively lowering the N doping efficiency. Furthermore, infrared measurements revealed the presence of CO2 molecules.