RF‐plasma assisted PLD growth of Zn3N2 thin films

Polycrystalline Zn3N2 films were prepared on sapphire and quartz substrates by reactive pulsed laser ablation of a metallic zinc target in a nitrogen plasma atmosphere using a frequency-doubled Nd:YAG laser, assisted by a 13.56 MHz radio-frequency (RF) plasma. The morphological, structural and optical properties are studied by Scanning Electron Microscopy, X-ray diffraction, transmittance and ellipsometric spectroscopy. SEM revealed a very smooth and crack-free film surface. X-ray diffraction indicates that the Zn3N2 films deposited at 400 °C substrate temperature are cubic in structure with no preferred orientation. The lattice constant has been estimated to be a = 0.97 nm. The absorption coefficient is deduced from the transmission spectra, and its dependence on photon energy is examined to determine the optical band gap. Refractive index and film thickness are deduced from spectroscopic ellipsometry measurements. Zn3N2 is determined to be a n-type semiconductor with a direct band gap of 3.2 eV. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)