We report on the demonstration of photodetectors based on large scale two-dimensional molybdenum disulfide (MoS2) transition metal dichalcogenides. Excellent film uniformity and precise control of the MoS2 thickness down to a monolayer (~0.75nm) were achieved by magnetron sputtering synthesis approach. In particular, the photodetectors integrated with five MoS2 monolayers exhibit a high photoresponsivity of 1.8 A/W, an external quantum efficiency exceeding 260%, and a photodetectivity of ~5 x 10(8) Jones for a wavelength of 850 nm, surpassing the performance of mechanically exfoliated based photodetectors.

Ge 3 N 4 dielectrics were prepared on Ge surface by in situ direct atomic source nitridation. The thermal stability and band alignments for Ge3N4∕Ge interfaces have been studied by using high-resolution x-ray photoemission spectroscopy. The in situ thermal treatment shows that Ge3N4 film has higher temperature thermal stability up to 550°C in vacuum. The conduction- and valence-band offsets at Ge3N4∕Ge interface are quite asymmetrical with the values of 2.22 and 1.11eV, respectively.

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Growth and characterization of Hf-aluminate high-k gate dielectric ultrathin films with equivalent oxide thickness less than 10 Å

The microstructure, static, and dynamic magnetic properties have been investigated for BaCoZnFe 16 O 27 doped with small amounts of V 2 O 5 from 0 to 1.5 wt %. The results show that the doping of V 2 O 5 can significantly improve the dynamic properties of W-type barium ferrites at microwave frequency. As compared to the undoped sample, the permeabilities 0 Ј and max Љ increase by about 42% and 67%, respectively, for the sample doped with 1.0 wt % of V 2 O 5 . Due to the V 2 O 5 doping, perfect hexagonal-plate grains are formed, leading to the decrease in the natural resonance frequency, due to the large demagnetizing effect. The predicted reflection loss shows that the maximum relative bandwidth W max = f up / f low reaches 3.9 for attenuation of more than 10 dB in the sample doped with 1.0 wt % of V 2 O 5 . This is a good candidate for electromagnetic materials with low reflectivity and broadband at microwave frequency.