Evaluation of the impact of TMIn flow rate on the structural and optical properties of InN/ZnO heterojunctions using RF-MOMBE

Abstract

Indium nitride (InN) films were deposited on Al2O3 substrates with a zinc oxide (ZnO) interlayer using by radio-frequency metalorganic molecular beam epitaxy (RF-MOMBE). We evaluated the impact of the flow rate of trimethylindium (In(CH3)3, TMIn) on the structure, surface morphology, and optical and electrical properties of the films using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis spectroscopy, and Hall measurements. The XRD results indicated that all InN films were formed from single-phase wurtzite crystals with the preferred orientations along the c-axis. The SEM images indicated that the rough surfaces of the InN films grown with TMIn flow rates less than 0.55sccm. The TEM images showed that InN and ZnO had hexagonal structures (wurtzite) that were epitaxially grown by RF-MOMBE on the substrates. The electron concentrations ranged from 7.3×1019 to 2.56×1020cm−3 of the InN films were measured.