Houping Yang

Bio: Houping Yang is an academic researcher from Shanghai University. The author has contributed to research in topics: Field-effect transistor & Schottky barrier. The author has co-authored 2 publications.

A comprehensive first-principle study of borophene-based nano gas sensor with gold electrodes

Abstract: Using density functional theory combined with nonequilibrium Green’s function method, the transport properties of borophene-based nano gas sensors with gold electrodes are calculated, and comprehensive understandings regarding the effects of gas molecules, MoS2 substrate and gold electrodes to the transport properties of borophene are made. Results show that borophene-based sensors can be used to detect and distinguish CO, NO, NO2 and NH3 gas molecules, MoS2 substrate leads to a nonlinear behavior on the current-voltage characteristic, and gold electrodes provide charges to borophene and form a potential barrier, which reduced the current values compared to the current of the systems without gold electrodes. Our studies not only provide useful information on the computationally design of borophene-based gas sensors, but also help understand the transport behaviors and underlying physics of 2D metallic materials with metal electrodes.

In-plane Schottky-barrier field-effect transistors with a 4-nm channel based on 1T/2H MoTe2 and WTe2

Abstract: As state-of-the-art fabrication techniques are approaching the 3 nm size, the traditional silicon-based circuit faces huge challenges. Transistors based on two-dimensional (2D) materials have attracted much attention as potential alternative candidates. However, critical performances including the subthreshold swing (SS), on/off ratio, and magnitude of the on-state current for 2D transistors around 3 nm size are far less to be studied well. In this work, we propose in-plane Schottky-barrier field-effect transistors (SBFETs) with a 4-nm channel based on the lateral heterostructure of monolayer 1T/2H MoTe2 and WTe2. The electric transport properties are investigated by first-principles quantum transport simulations. At a 0.64 V bias, the WTe2 SBFET has an on-state current of 3861 μA/μm, with a 4.5 × 104 on/off ratio and an SS of 87 mV/dec, while the MoTe2 SBFET has an on-state current of 1480 μA/μm, with a large on/off rate of 3.6 × 105 and an SS of 78 mV/dec. Our results suggest that FETs based on the lateral heterostructure of 1T/2H MoTe2 (WTe2) are promising candidates for high-performance 2D transistors.

Impact of Process Induced Strain on the Sensitivity of Charge Plasma Doped TMD TFET Biosensor

Abstract: In this work for the first time, we design and investigate the impact of process-induced strain on the sensitivity of a Charge Plasma TMD Tunnel FET-based dielectric modulated biosensor. Monolayer WTe2 acts as the source, channel, and drain materials in the proposed biosensor. The channel material undergoes uniaxial strain due to process-induced strain and its impact on the material characteristics has been taken advantage of to enhance the proposed biosensor's sensitivity. The Charge Plasma doping technology has been utilized to reduce costs, streamline production, and lessen random dopant fluctuations. Quantum Espresso software has been used to perform first principle calculations based on density functional theory (DFT) to determine the material's electronic characteristics. SILVACO TCAD, a 2-D device simulator has been utilized to simulate the electrical characteristics of the proposed biosensor. The proposed biosensor (for k=8) has attained a very high sensitivity of 100000. Finally, the proposed biosensor is benchmarked with contemporary 2-D material-based biosensors and it has been observed that the presented Charge Plasma TMD TFET-based biosensor has emerged to have a superior sensitivity which is ~ 3 decades higher than the maximum sensitivity reported by other alternatives.