Reactive pulsed laser deposition of InN thin films

摘要

III-V nitrides group are promising materials for technological applications such as: semiconductor lasers, light emitting diodes, optical detectors and refractory materials. In addition, transistors based on the group III nitrides should operate at higher temperatures and under more adverse conditions than similar devices on silicon, II-VI materials, or other III-V materials, due to the high band gap, the strong chemical bonds and the high chemical inertness of the nitrides. The paper reports the first results concerning the deposition of InN thin films by reactive laser ablation of indium target in nitrogen atmosphere. A XeCl excimer laser (λ = 308 nm, τ = 30 ns) was used as laser source. The laser beam was incident on the target with an angle of 45°, laser fluency was set at 5 J/cm~2. In order to achieve uniform irradiation condition and to avoid fast drilling, the target was rotated with 180 rpm. KBr, Si and sapphire substrates were positioned at 3.5 cm from the target and parallel to it. The nitrogen pressure during deposition was set at 1 * 10~(-4), 5 * 10~(-3) and 5 * 10~(-1) mbar, respectively. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDAX), and X-ray Diffraction (XRD) analysis were carried out in order to check the composition, structure and the surface aspect of the deposited layers.