Influence of nitrogen flux on structural and optical properties of InN films fabricated by PAMBE

The InN epilayers on nitrided sapphire substrates under different nitrogen fluxes by plasma-assisted molecular beam epitaxy (PAMBE). InN epilayers were prepared on nitrided sapphire substrates by plasma-assisted molecular beam epitaxy (PAMBE) using nitrogen and trimethylindium precursor as the V/III sources. The influence of he nitrogen flux on the film structure, surface morphology and optical and electrical properties were thoroughly studied. The InN films were deposited on sapphire substrates by PAMBE system with the background pressure. For the group-V source, N2 gas before flowing into the chamber was decomposed to atomic nitrogen by applying the RF plasma. In all samples, sapphire nitridation was performed at 700°C for 30 min after thermal cleaning at 800°C to decrease the lattice mismatch for the subsequent growth of InN layers. all the InN samples displayed only two diffraction peaks corresponding to the InN (0002) and (0004) diffractions except for the Al2O3 substrate reflection, indicating that the as-grown InN epilayers with a significant diffraction had a highly c-axis preferred orientation growth. It was also found that, as the nitrogen flux increased, the intensity of InN diffraction from sample (A) to (C) increased due to more crystallites have grown in the structure.