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We have demonstrated that the thickness of the catalyst layer plays a significant role in the morphology and the material quality of the InN nanocolumns grown on Si(111) substrate by plasma-assisted molecular beam expitaxy using vapor-liquid-solid method. A systematic investigation of In catalyst films was undertaken, revealing that high density uniform InN can not be obtained when the In catalyst is either too thin or too thick and the appropriate thickness of the deposited In was 1 nm. The influence of V/III radio on the growth procedure is also discussed, and as proved, a higher V/III radio is necessary to be used to get high density nanocolumns and improved optical property. [ABSTRACT FROM AUTHOR]

Through Indium beam irradiation toward the substrate before growing, high density uniform InN nanocolumns were obtained on p-GaAs(0 0 1) substrate and their possible one dimensional (1D) growth mechanism was analyzed. Rocking curves of all samples showed that Indium beam irradiation method had improved the crystal quality largely, which might be an effective way to release the strain between hexagonal InN(0 0 0 1) and cubic GaAs(0 0 1) with large lattice mismatch. Through quantitative analysis of XPS spectra gotten by in situ measurement, it was found that the InN stoichiometric ratio of all three samples were close to 1:1, which revealed that there was no residual metal at the tip of our nanocolumns. No catalyst or residual metal left could keep its electronic and optical property intact. All three samples showed strong photoluminescence at room temperature. To effectively release the strain and get well surface and interface are important for heterojunction optoelectronic device based on InN. [ABSTRACT FROM AUTHOR]

The n-InN/p-NiO/GaN heterojunction was fabricated by using plasma-assisted molecular beam epitaxy (PAMBE) combined with radio frequency magnetron sputtering. The device exhibited typical rectification characteristic with a turn-on voltage of ~1.5 V. Under forward bias, a dominant near infrared emission (NIR) peaked around 1565 nm was detected at room temperature. The NIR emission was attributed to the band-edge emission of InN film according to the photoluminescence spectrum of InN layer. Furthermore, the mechanism of the current transport and light emission was tentatively discussed in terms of the band diagrams of the heterojunction. [ABSTRACT FROM AUTHOR]

The NiO films were prepared on GaN substrate by depositing an InN epilayer on GaN by plasma-assisted molecular beam epitaxy (PAMBE) and then growing NiO films on InN epilayer by radio frequency (rf) magnetron sputtering. We studied the effect of InN epilayers on structure, surface morphology, electrical and optical properties of NiO films using X-ray diffraction (XRD), scanning electron microscopy (SEM), Hall and optical absorption measurement. It was found that the NiO films grown with InN epilayer exhibited better crystalline qualities with more coalescent surface morphologies and an enhancement of the electrical properties. Moreover, the effect of vacuum annealing on the crystalline qualities of the NiO films was also investigated. [ABSTRACT FROM AUTHOR]

InN epilayers were deposited on nitrided sapphire substrates using plasma-assisted molecular beam epitaxy (PAMBE) system. The physical properties of InN films under different growth temperatures were thoroughly studied. The XRD results indicated that as-prepared InN films without Indium droplets were preferentially oriented in the c-axis direction. The SEM results showed that the InN films grown in a two-dimensional mode with a thickness of ∼200 nm under the growth temperature of 460 °C. In addition, the optical absorption measurement exhibited that the energy bandgap of InN films was around 0.75–0.81eV and the PL spectra of the epilayers revealed an infrared emission. Moreover, the electrical properties of the films were discussed by Hall effect in detail. [ABSTRACT FROM AUTHOR]

InN epilayers were prepared on c -plane (0001) sapphire substrates by plasma-assisted molecular beam epitaxy (PAMBE). We studied the effect of nitridation on structure, surface morphology, electrical and optical properties of InN films using X-ray diffraction (XRD), Reflection high-energy electron diffraction (RHEED), scanning electron microscopy (SEM), atomic force microscopy (AFM), Hall and photoluminescence (PL) measurement. The results showed a significant improvement of the crystalline qualities and surface morphologies and enhancement of the electrical and optical properties for InN films grown after nitridation. Moreover, the energy band-gap of InN films were also determined by optical absorption and photoluminescence (PL) measurement. [ABSTRACT FROM AUTHOR]