Formation and Applications in Electronic Devices of Lattice-Aligned Gallium Oxynitride Nanolayer on Gallium Nitride.

Gallium nitride (GaN), a promising alternative semiconductor to Si, is widely used in photoelectronic and electronic technologies. However, the vulnerability of the GaN surface is a critical restriction that hinders the development of GaN-based devices, especially in terms of device stability and reliability. In this study, this challenge is overcome by converting the GaN surface into a gallium oxynitride (GaON) epitaxial nanolayer through an in situ two-step "oxidation-reconfiguration" process.

Bridging the gap between atomically thin semiconductors and metal leads.

Electrically interfacing atomically thin transition metal dichalcogenide semiconductors (TMDSCs) with metal leads is challenging because of undesired interface barriers, which have drastically constrained the electrical performance of TMDSC devices for exploring their unconventional physical properties and realizing potential electronic applications. Here we demonstrate a strategy to achieve nearly barrier-free electrical contacts with few-layer TMDSCs by engineering interfacial bonding distortion. The carrier-injection efficiency of such electrical junction is substantially increased with robust ohmic behaviors from room to cryogenic temperatures.

Two-dimensional ferroelectric MoS/GaO heterogeneous bilayers with highly tunable photocatalytic and electrical properties.

Two-dimensional van der Waals heterostructures with strong intrinsic ferroelectrics are highly promising for novel devices with designed electronic properties. The polarization reversal transition of the 2D ferroelectric GaO monolayer offers a new approach to tune the photocatalytic and electrical properties of MoS/GaO heterogeneous bilayers. In this work, we study MoS/GaO heterogeneous bilayers with different intrinsic polarization using hybrid-functional calculations.

Two-Dimensional Gallium Oxide Monolayer for Gas-Sensing Application.

A two-dimensional (2D) GaO monolayer with an asymmetric quintuple-layer configuration was reported as a novel 2D material with excellent stability and strain tunability. This unusual asymmetrical structure opens up new possibilities for improving the selectivity and sensitivity of gas sensors by using selected surface orientations. In this study, the surface adsorptions of nine molecular gases, namely, O, CO, CO, SO, NO, HS, NO, NH, and HO, on the 2D GaO monolayer are systematically investigated through first-principles calculations.

Tunable Properties of Novel GaO Monolayer for Electronic and Optoelectronic Applications.

A novel two-dimensional (2D) GaO monolayer was constructed and systematically investigated by first-principles calculations. The 2D GaO has an asymmetric configuration with a quintuple-layer atomic structure, the same as the well-studied α-InSe, and is expected to be experimentally synthesized. The dynamic and thermodynamic calculations show excellent stability properties of this monolayer material.

Enhanced dielectric deposition on single-layer MoS with low damage using remote N plasma treatment.

Using remote N plasma treatment to promote dielectric deposition on the dangling-bond free MoS is explored for the first time. The N plasma induced damages are systematically studied by the defect-sensitive acoustic-phonon Raman of single-layer MoS, with samples undergoing O plasma treatment as a comparison. O plasma treatment causes defects in MoS mainly by oxidizing MoS along the already defective sites (most likely the flake edges), which results in the layer oxidation of MoS.

Improved Gate Dielectric Deposition and Enhanced Electrical Stability for Single-Layer MoS2 MOSFET with an AlN Interfacial Layer.

Transistors based on MoS2 and other TMDs have been widely studied. The dangling-bond free surface of MoS2 has made the deposition of high-quality high-k dielectrics on MoS2 a challenge. The resulted transistors often suffer from the threshold voltage instability induced by the high density traps near MoS2/dielectric interface or inside the gate dielectric, which is detrimental for the practical applications of MoS2 metal-oxide-semiconductor field-effect transistor (MOSFET).