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Philip X.-l. Feng - One of the best experts on this subject based on the ideXlab platform.

  • Molybdenum Disulfide (Mos2) nanoelectromechanical resonators with on-chip aluminum nitride (AlN) piezoelectric excitation
    2018 IEEE Micro Electro Mechanical Systems (MEMS), 2018
    Co-Authors: Xu-qian Zheng, Muhammad Faizan, Tom Larsen, Luis Guillermo Villanueva, Philip X.-l. Feng
    Abstract:

    We report on the first experimental demonstration of vibrating two-dimensional nanoelectromechanical systems (2D NEMS) with on-chip piezoelectric excitation. Combining a wafer-scale aluminum nitride (AlN) thin film technology with an all-dry transfer technique for atomic layer 2D semiconductors, we fabricate and piezoelectrically excite few-atomic-layer Molybdenum Disulfide (Mos2) NEMS resonators in the high frequency (HF) band. Multimode resonances up to 38MHz are observed, with efficient electromechanical drive from the AlN layer off the vibrating 2D NEMS device region (to avoid compromising the movable 2D device by electrodes needed for on-chip excitation and readout). The piezoelectrically excited 2D NEMS resonators may enable remotely driven, ultrasensitive transducers. Combined with on-chip electrical readout techniques (e.g., mixing), this device platform also holds promise for future radio frequency (RF) electronics and integrated systems.

  • Gallium selenide (GaSe)-Molybdenum Disulfide (Mos2) van der Waals heterojunction diodes
    2017 75th Annual Device Research Conference (DRC), 2017
    Co-Authors: Arnob Islam, Philip X.-l. Feng
    Abstract:

    van der Waals (vdW) heterostructures enabled by two-dimensional (2D) semimetals and semiconductors [1] have shown interesting attractions and great promises toward realizing future-generation high performance electronic and optoelectronic devices. In this study, we demonstrate gallium selenide (GaSe) (p-type) /Molybdenum Disulfide (Mos2) (n-type) heterojunction. This heterojunction shows p-n junction diode behavior with good rectification ratio of ~103 at zero gate voltage. In addition, it shows gate tunable behavior with n-type characteristics. Furthermore, we characterize photoresponse of the device under 532 nm laser illumination and obtain photoresponsivity of ~71 mA/W.

  • effects of γ ray radiation on two dimensional Molybdenum Disulfide Mos2 nanomechanical resonators
    Applied Physics Letters, 2016
    Co-Authors: Matthew J Krupcale, Philip X.-l. Feng
    Abstract:

    We report on experimental investigation and analysis of γ-ray radiation effects on two-dimensional Molybdenum Disulfide (Mos2) drumhead nanomechanical resonators vibrating at megahertz frequencies. Given calibrated dosages of γ-ray radiation of ∼5000 photons with energy at 662 keV, upon exposure over 24 or 12 h, all the Mos2 resonators exhibit ∼0.5–2.1% resonance frequency upshifts due to the ionizing γ-ray induced charges and their interactions. The devices show γ-ray photon responsivity of ∼30–82 Hz/photon, with an intrinsic γ-ray sensitivity (limit of detection) estimated to approach ∼0.02–0.05 photon. After exposure expires, resonance frequencies return to an ordinary tendency where the frequency variations are dominated by long-term drift. These γ-ray radiation induced frequency shifts are distinctive from those due to pressure variation or surface adsorption mechanisms. The measurements and analyses show that Mos2 resonators are robust yet sensitive to very low dosage γ-ray, demonstrating a potentia...

  • Molybdenum Disulfide Mos2 nanomechanical resonators integrated on microchannels
    Volume 3: Advanced Fabrication and Manufacturing; Emerging Technology Frontiers; Energy Health and Water- Applications of Nano- Micro- and Mini-Scale , 2015
    Co-Authors: Rui Yang, Zhenyu Li, Philip X.-l. Feng
    Abstract:

    We report on experimental demonstration of multilayer Molybdenum Disulfide (Mos2) nanomechanical resonators integrated on microchannels, with the potential for resonant operation and sensing applications in microfluidics. Microchannels with width of ∼5μm and depth of ∼1–2μm are fabricated on polydimethylsiloxane (PDMS) substrate. We transfer Mos2 flakes with both singly-clamped cantilever and doubly-clamped membrane structure onto the PDMS channels, and measure both undriven thermomechanical resonances and optically driven responses from the devices. The devices show up to 6 thermomechanical resonances, with highest resonance frequency (fres) of 16.3MHz and quality (Q) factor ∼200. This type of Mos2 nanomechanical resonators, when integrated with microfluidics in microchannels, would make new interesting candidates for biosensing and chemical sensing in fluids.© 2015 ASME

  • Observation of strong temperature hysteresis in Molybdenum Disulfide (Mos2) vibrating nanomechanical resonators
    2015 Joint Conference of the IEEE International Frequency Control Symposium & the European Frequency and Time Forum, 2015
    Co-Authors: Zenghui Wang, Rui Yang, Arnob Islam, Philip X.-l. Feng
    Abstract:

    We report experimental investigation of resonant responses of Molybdenum Disulfide (Mos2) nanomechanical resonators at different temperatures. We observe strong temperature hysteresis in measurements. By examining devices with different geometries under different air pressures, we determine that surface adsorption plays an important role in the observed temperature hysteresis. This opens new possibilities for studying surface processes using 2D nanomechanical resonators.

Han Zhang - One of the best experts on this subject based on the ideXlab platform.

  • ytterbium doped fiber laser passively mode locked by few layer Molybdenum Disulfide Mos2 saturable absorber functioned with evanescent field interaction
    Scientific Reports, 2015
    Co-Authors: Juan Du, Yu Chen, Qingkai Wang, Guobao Jiang, Changwen Xu, Chujun Zhao, Yuanjiang Xiang, Shuangchun Wen, Han Zhang
    Abstract:

    By coupling few-layer Molybdenum Disulfide (Mos2) with fiber-taper evanescent light field, a new type of Mos2 based nonlinear optical modulating element had been successfully fabricated as a two-dimensional layered saturable absorber with strong light-matter interaction. This Mos2-taper-fiber device is not only capable of passively mode-locking an all-normal-dispersion ytterbium-doped fiber laser and enduring high power laser excitation (up to 1 W), but also functions as a polarization sensitive optical modulating component (that is, different polarized light can induce different nonlinear optical response). Thanks to the combined advantages from the strong nonlinear optical response in Mos2 together with the sufficiently-long-range interaction between light and Mos2, this device allows for the generation of high power stable dissipative solitons at 1042.6 nm with pulse duration of 656 ps and a repetition rate of 6.74 MHz at a pump power of 210 mW. Our work may also constitute the first example of Mos2-enabled wave-guiding photonic device, and potentially give some new insights into two-dimensional layered materials related photonics.

Harith Ahmad - One of the best experts on this subject based on the ideXlab platform.

Shangjian Zhang - One of the best experts on this subject based on the ideXlab platform.

  • ultrafast erbium doped fiber laser mode locked by a cvd grown Molybdenum Disulfide Mos2 saturable absorber
    Optics Express, 2014
    Co-Authors: Heping Li, Chun Li, Xiaoxia Zhang, Shangjian Zhang
    Abstract:

    We demonstrate an erbium-doped fiber laser passively mode-locked by a multilayer Molybdenum Disulfide (Mos2) saturable absorber (SA). The multilayer Mos2 is prepared by the chemical vapor deposition (CVD) method and transferred onto the end-face of a fiber connector. Taking advantage of the excellent saturable absorption of the fabricated Mos2-based SA, stable mode locking is obtained at a pump threshold of 31 mW. Resultant output soliton pulses have central wavelength, spectral width, pulse duration, and repetition rate of 1568.9 nm, 2.6 nm, 1.28 ps, and 8.288 MHz, respectively. The experimental results show that multilayer Mos2 is a promising material for ultrafast laser systems.

Yu Chen - One of the best experts on this subject based on the ideXlab platform.