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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]

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]

Abstract: Normally, surface of c-axis oriented YBCO films grown by MOCVD are found to be populated by micron-sized outgrowths with elemental compositions such as Ba–Cu–O and Cu–O. For both low and high current applications with the YBCO films, these surface outgrowths should be eliminated. In this study, it is found that by using a simple processing technique of decreasing appropriately the sublimation temperature of the Cu-based precursor, the surface outgrowths can be essentially subdued. At the same time it is qualitatively predictable that J c of these smoother YBCO films will be lowered. However, experimentally, it is found that at appropriate YBCO film growth conditions, the lowered J c value is acceptable for most applications. Actually, a surface outgrowth covered YBCO film made by photo-assisted MOCVD, with film composition Y:Ba:Cu as 1:1.2:1.5, has its J c being 3.4MA/cm2 (0T, 77K). As composition of YBCO film is changed to 1:0.9:1.2 by lowering the sublimation rate of the Cu-based precursor, then there are no more outgrowths on surface, with its J c being 2.6MA/cm2. [Copyright &y& Elsevier]

Abstract: Zinc oxide (ZnO) thin film was grown on CaF2 (11–21) substrate by metalorganic vapor phase epitaxy (MOVPE) and the structure, surface morphology and the opto-electrical properties of the film were investigated. It was found that preferential c-axis oriented ZnO film was highly transparent and quite smooth. In photoluminescence (PL) spectrum at 10K, the neutral donor bound exciton (D0X) emission was identified at 3.362eV (I4), the neutral acceptor bound exciton (A0X) emission at 3.346eV (I9). Free A- and B-exciton emissions at 3.374eV and 3.386eV, respectively, as well as the phonon replicas of free A-exciton and D0X were also observed, indicating high optical quality of the ZnO film. Temperature-dependent PL spectra demonstrated that the free exciton emission was dominant at a temperature larger than 215K. Hall measurement showed that the ZnO/CaF2 film exhibited n-type conduction, with the resistivity of 114Ωcm and the Hall mobility of 15.7cm2/Vs. [Copyright &y& Elsevier]