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Large size monolayer Molybdenum disulphide (MoS2) was successfully grown by chemical vapor deposition method under an atmospheric pressure. The electrical transport properties of the fabricated back-gate monolayer MoS2 field effect transistors (FETs) were investigated under low temperatures; a peak field effect mobility of 59 cm2V–1s–1 was achieved. With the assist of Raman measurement under low temperature, this work identified the mobility limiting factor for the monolayer MoS2 FETs: homopolar phonon scattering under low temperature and electron-polar optical phonon scattering at room temperature. [ABSTRACT FROM AUTHOR]

ZnO microrods (whiskers) were fabricated by a simple thermal oxidation method. The morphologies of the samples were detected by the scanning electron microscope, which showed the ZnO microrods were about 30 μm long with a diameter of 1–2 μm. In the photoluminescence (PL) spectra, only the exciton related emission bands in the ultraviolet region could be obtained at room temperature. And, a new emission band due to the exciton–exciton collision process was observed at the low energy side of the free exciton emission under the excitation intensity of 2.1 kW/cm[sup 2]. This emission band increased nonlinearly. When the excitation intensity was increased above 16 kW/cm[sup 2] some fine structures could also be seen clearly in the PL spectra. These fine structures originated from the cavity modes of the Fabry–Pérot étalon. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

This paper reported AlGaN/GaN high electron mobility transistors (HEMTs) with low sub-threshold swing SS on free-standing GaN wafer. High quality AlGaN/GaN epi-layer has been grown by metal-organic chemical vapor deposition (MOCVD) on free-standing GaN, small full-width hall maximum (FWHM) of 42.9 arcsec for (0002) GaN XRD peaks and ultralow dislocation ~104-105 cm-2) were obtained. Due to these extremely high quality material properties, the fabricated AlGaN/GaN HEMTs achieve a low SS ( ~60 mV/decade), low hysteresis of 54 mV, and high peak electron mobility μeff of ~1456 cm2V-1s-1. Systematic study of materials properties and device characteristics exhibits that GaN-on-GaN AlGaN/GaNHEMTs are promising candidate for next generation high power device applications. [ABSTRACT FROM AUTHOR]

The energy band alignment between ZnO and multilayer (ML)-MoS2 was characterized using high-resolution x-ray photoelectron spectroscopy. The ZnO film was deposited using an atomic layer deposition tool, and ML-MoS2 was grown by chemical vapor deposition. A valence band offset (VBO) of 3.32 eV and a conduction band offset (CBO) of 1.12eV were obtained for the ZnO/ ML-MoS2 interface without any treatment. With CHF3 plasma treatment, a VBO and a CBO across the ZnO/ML-MoS2 interface were found to be 3.54 eV and 1.34 eV, respectively. With the CHF3 plasma treatment, the band alignment of the ZnO/ML-MoS2 interface has been changed from type II or staggered band alignment to type III or misaligned one, which favors the electron-hole pair separation. The band alignment difference is believed to be dominated by the down-shift in the core level of Zn 2p or the interface dipoles, which is caused by the interfacial layer rich in F. [ABSTRACT FROM AUTHOR]

The energy band alignment between HfO2/multilayer (ML)-MoS2 was characterized using high-resolution x-ray photoelectron spectroscopy. The HfO2 was deposited using an atomic layer deposition tool, and ML-MoS2 was grown by chemical vapor deposition. A valence band offset (VBO) of 1.98 eV and a conduction band offset (CBO) of 2.72 eV were obtained for the HfO2/ML-MoS2 interface without any treatment. With CHF3 plasma treatment, a VBO and a CBO across the HfO2/ML-MoS2 interface were found to be 2.47 eV and 2.23 eV, respectively. The band alignment difference is believed to be dominated by the down-shift in the core level of Hf 4d and up-shift in the core level of Mo 3d, or the interface dipoles, which caused by the interfacial layer in rich of F. [ABSTRACT FROM AUTHOR]

FeSe films have been grown on GaAs (001) substrates by low-pressure metal organic vapor deposition at different temperatures. X-ray diffraction analysis indicated that the FeSe films grown at substrate temperatures (Ts) between 220 and 340 °C were preferentially oriented with tetragonal structure. It was not possible to deposit films at Ts above 400 °C. The atomic molar ratios of Se/Fe increased with increasing the flow rate of H2Se/Fe(CO)5 and the growth temperature. The electronic property results showed that the conductive type of FeSe could be adjusted by controlling the growth temperature. The coercivity of FeSe decreased with increasing the growth temperature from 220 to 300 °C due to the improvement of crystal quality. [ABSTRACT FROM AUTHOR]