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Transition metal dichalcogenide (TMD) atomic layers are an atomically thin material in the form of MX2, where M is a transition metal atom (such as Mo or W) and X is a chalcogen atom (such as S, Se, or Te). Among them, MoTe2 is attractive because of its narrow band gap (i.e., ~ 1 eV), leading to optical and electrical applications such as field-effect transistors, photodetectors, lightemitting diodes, and photovoltaics. The TMD atomic layers, however, suffer from the extremely high contact resistance of the metal electrodes. The formation of a low-resistance ohmic contact is essential to achieving good device performance. Here, we examined the contact resistance of the two-dimensional MoTe2 atomic tri-layers from transmission line model (TLM) measurements. 2H-phase MoTe2 atomic tri-layers were synthesized on a silicon dioxide/silicon substrate by using metal-organic chemical vapor deposition. The TLM pattern was fabricated on the tri-layers to examine the specific contact resistance of metals. This method is highly effective for minimizing the contact resistance of TMD atomic layers.

A ternary InAsyP1−y alloy is suitable for an application to near-infrared (NIR) optical devices as their direct bandgap energy covers the entire NIR band. A nanowire (NW) system allows an epitaxial integration of InAsyP1−y alloy on any type of substrate since the lattice mismatch strain can be relieved through the NW sidewall. Nevertheless, the very large surface to volume ratio feature of the NWs leads to enormous surface states which are susceptible to surface recombination of free carriers. Here, ternary InAs0.75P0.25 NWs are grown with InP passivation layer (i.e., core–shell structure) to minimize the influence of the surface states, thus increasing their optical and electrical properties. A photoresponse study was achieved through the modeled band structure of the grown NWs. The model and experimental results suggest that 5-nm-thick InP shell efficiently passivates the surface states of the InAs0.75P0.25 NWs. The fabricated core–shell photodetectors and field-effect transistors exhibit improved photoresponse and transport properties compared to its counterpart core-only structure.

The electromechanical properties of ternary InAsP nanowires (NWs) were investigated by applying a uniaxial tensile strain in a transmission electron microscope (TEM). The electromechanical properties in our examined InAsP NWs were governed by the piezoresistive effect. We found that the electronic transport of the InAsP NWs is dominated by space-charge-limited transport, with a I ∞ V2 relation. Upon increasing the tensile strain, the electrical current in the NWs increases linearly, and the piezoresistance gradually decreases nonlinearly. By analyzing the space-charge-limited I–V curves, we show that the electromechanical response is due to a mobility that increases with strain. Finally, we use dynamical measurements to establish an upper limit on the time scale for the electromechanical response.

A double layered plasmonic device based on transferring technique with polystyrene nano-beads is analyzed and demonstrated to increase the sensing characteristics of plasmonic sensor system. The double layered plasmonic devices are calculated using the three-dimensional finite-difference time-domain method for the width and thickness of the nano-hole structures. The double layered plasmonic devices with different diameters of the Au nano-hole are fabricated by transferring method with commercially available chloromethyl latex with a diameter of 0.42 μm. The optimum sensing characteristic of the proposed plasmonic device is obtained with the film and the hole thickness of 15 and 15 nm in the 246 nm wide nano-hole size. The best sensitivity of the proposed plasmonic sensor is 67.7 degree/RIU when the sensitivity of the conventional plasmonic sensor is 42.2 degree/RIU.