Growth of High Mobility InN Film on Ga-Polar GaN Substrate by Molecular Beam Epitaxy for Optoelectronic Device Applications

The fabrication of high-speed electronic and communication devices has rapidly grown the demand for high mobility semiconductors. However, their high cost and complex fabrication process make them less attractive for the consumer market and industrial applications. Indium nitride (InN) can be a potential candidate to fulfill industrial requirements due to simple and low-cost fabrication process as well as unique electronic properties such as narrow direct bandgap and high electron mobility. In this work, 3 mu m thick InN epilayer is grown on (0001) gallium nitride (GaN)/Sapphire template under In-rich conditions with different In/N flux ratios by molecular beam epitaxy. The sharp InN/GaN interface monolayers with the In-polar growth are observed, which assure the precise control of the growth parameters. The directly probed electron mobility of 3610 cm(2) V-1 s(-1) is measured with an unintentionally doped electron density of 2.24 x 10(17) cm(-3). The screw dislocation and edge dislocation densities are calculated to be 2.56 x 10(8) and 0.92 x 10(10) cm(-2), respectively. The step-flow growth with the average surface roughness of 0.23 nm for 1 x 1 mu m(2) is confirmed. The high quality and high mobility InN film make it a potential candidate for high-speed electronic/optoelectronic devices.