The influence of the LT-InN buffer growth conditions on the quality of InN films grown on Si(1 1 1) substrate by MBE

Abstract

This work aims to explore the effect of the growth conditions of low-temperature InN (LT-InN) buffer layers on the quality of wurtzite InN films grown on Si(1 1 1) substrates by plasma-assisted molecular beam epitaxy (PA-MBE). Experimental results indicated that higher growth rate and lower thickness of LT-InN buffer layer guarantee better crystalline quality and optical properties for InN films grown at the same temperature. The crystalline quality of the InN epilayers was investigated by high-resolution X-ray diffraction (XRD) performed on the reflection plans of various inclination angles. XRD study confirmed that the dominating threading dislocation was edge type. Surface morphology was measured by atomic force microscope (AFM), and optical property was characterized by photoluminescence (PL). The best InN film was obtained from the sample with a 20 nm LT-InN buffer layer, 140 nm/h growth rate, and 500 °C HT-InN growth temperature. The characterization results showed 2.785×10 10 cm –2 edge-type dislocation density estimated by XRD, 11.57 nm AFM RMS roughness, and 0.666 eV near band-edge PL transition at 15 K with 24 meV broadening.