作者：Shao, Q. M.*;  Yu, G. Q.;  Lan, Y. W.;  Shi, Y. M.;  Li, M. Y.;  Zheng, C.;  Zhu, X. D.;  Li, L. J.;  Amiri, P. K.; Wang, K. L*

发表杂志：2016 年 Nano Letters 卷 16 期 12 页 7514-7520

Abstract

The electronic and optoelectronic properties of two-dimensional materials have been extensively explored in graphene and layered transition metal dichalcogenides (TMDs). Spintronics in these two-dimensional materials could provide novel opportunities for future electronics, for example, efficient generation of spin current, which should enable the efficient manipulation of magnetic elements. So far, the quantitative determination of charge current-induced spin current and spin orbit torques (SOTs) on the magnetic layer adjacent to two-dimensional materials is still lacking. Here, we report a large SOT generated by current-induced spin accumulation through the Rashba-Edelstein effect in the composites of monolayer TMD (MoS2 or WSe2)/CoFeE bilayer. The effective spin conductivity corresponding to the SOT turns out to be almost temperature-independent. Our results suggest that the charge-spin conversion in the chemical vapor deposition-grown large-scale monolayer TMDs could potentially lead to high energy efficiency for magnetization reversal and convenient device integration for future spintronics based on two-dimensional materials.

作者：Tangi, M.;  Mishra, P.;  Ng, T. K.;  Hedhili, M. N.;  Janjua, B.;  Alias, M. S.;  Anjum, D. H.;  Tseng, C.-C.;  Shi, Y.;  Joyce, H. J.;  Li, L.-J.; Ooi, B. S.*

发表杂志：2016年 Applied Physics Letters 卷 109 期 3

Abstract

We report the band alignment parameters of the GaN/single-layer (SL) MoS2 heterostructure where the GaN thin layer is grown by molecular beam epitaxy on CVD deposited SL-MoS2/c-sapphire. We confirm that the MoS2 is an SL by measuring the separation and position of room temperature micro-Raman E-2g(1) and A(g)(1) modes, absorbance, and micro-photoluminescence bandgap studies. This is in good agreement with HRTEM cross-sectional analysis. The determination of bandoffset parameters at the GaN/SL-MoS2 heterojunction is carried out by high-resolution X-ray photoelectron spectroscopy accompanying with electronic bandgap values of SL-MoS2 and GaN. The valence band and conduction band offset values are, respectively, measured to be 1.86 +/- 0.08 and 0.56 +/- 0.1 eV with type II band alignment. The determination of these unprecedented bandoffset parameters opens up a way to integrate 3D group III nitride materials with 2D transition metal dichalcogenide layers for designing and modeling of their heterojunction based electronic and photonic devices.

作者：Tsung Sheng, K.;  Hau-Vei, H.;  Ang-Yu, L.;  Li-Syuan, L.;  Jing-Kai, H.;  Hao-Chung, K.*;  Wen-Hao, C.;  Lain-Jong, L.; Yumeng, S

发表杂志：2016 Conference on Lasers and Electro-Optics (CLEO)

Abstract

We demonstrate that the photoluminescence emission intensity of the CVD-grown MoSe2monolayers can be effectively enhanced more than 30 times after a simple hydrohalic acidtreatment, providing the cost-effect manufacturing of atomically-thin two-dimensional semiconductor materials.

作者：Li Ming-Yang, Shi Yumeng, Cheng Chia-Chin, Lu Li-Syuan, Lin Yung-Chang, Tang Hao-Lin, Tsai Meng-Lin, Chu Chih-Wei, Wei Kung-Hwa, He Jr-Hau, Chang Wen-Hao, Suenage Kazu, Li Lain-Jong*

发表杂志：2015 年 Science 卷 349 期 6247 页 524-528

Abstract

Two-dimensional transition metal dichalcogenides (TMDCs) such as molybdenum sufide MoS2 and tungsten sufide WSe2 have potential applications in electronics because they exhibit high on-off current ratios and distinctive electro-otical properties. Spatially connected TMDC lateral heterojuctions are key components for constructing monolayer p-n rectifying diodes, light-emitting diodes, photovoltaic devices, and bipolar junction transistors. However, such structures are not readily prepared via the layer-stacking techniques, and direct growth favors the thermodynamically preferred TMDC alloys. We report the two-step epitaxial growth of lateral WSe2-MoS2 heterojuction, where the edge of WSe2 induces the epitaxial MoS2 growth despite a large lattice mismatch. The epitaxial growth process offers a controllable method to obtain lateral heterojunction with an atomically sharp interface.