Computational Assessment of - Curves and Tunability of 2D Semiconductor van der Waals Heterostructures.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have received significant interest for use in tunnel field-effect transistors (TFETs) due to their ultrathin layers and tunable band gap features. In this study, we used density functional theory (DFT) to investigate the electronic properties of six TMD heterostructures, namely, MoSe/HfS, MoTe/ZrS, MoTe/HfS, WSe/HfS, WTe/ZrS, and WTe/HfS, focusing on variations in band alignments. We demonstrate that WTe/ZrS and WTe/HfS have the smallest band gaps (close to 0 or broken) from the considered set.

Epitaxy of GaSe Coupled to Graphene: From In Situ Band Engineering to Photon Sensing.

2D semiconductors can drive advances in quantum science and technologies. However, they should be free of any contamination; also, the crystallographic ordering and coupling of adjacent layers and their electronic properties should be well-controlled, tunable, and scalable. Here, these challenges are addressed by a new approach, which combines molecular beam epitaxy and in situ band engineering in ultra-high vacuum of semiconducting gallium selenide (GaSe) on graphene.

Single-photon detection using large-scale high-temperature MgB sensors at 20 K.

Ultra-fast single-photon detectors with high current density and operating temperature can benefit space and ground applications, including quantum optical communication systems, lightweight cryogenics for space crafts, and medical use. Here we demonstrate magnesium diboride (MgB) thin-film superconducting microwires capable of single-photon detection at 1.55  μm optical wavelength.

Bottom-Up Growth of Monolayer Honeycomb SiC.

The long theorized two-dimensional allotrope of SiC has remained elusive amid the exploration of graphenelike honeycomb structured monolayers. It is anticipated to possess a large direct band gap (2.5 eV), ambient stability, and chemical versatility.

Electric Field and Strain Tuning of 2D Semiconductor van der Waals Heterostructures for Tunnel Field-Effect Transistors.

Heterostacks consisting of low-dimensional materials are attractive candidates for future electronic nanodevices in the post-silicon era. In this paper, using first-principles calculations based on density functional theory (DFT), we explore the structural and electronic properties of MoTe/ZrS heterostructures with various stacking patterns and thicknesses. Our simulations show that the valence band (VB) edge of MoTe is almost aligned with the conduction band (CB) edge of ZrS, and (MoTe)/(ZrS) ( = 1, 2) heterostructures exhibit the long-sought broken gap band alignment, which is pivotal for realizing tunneling transistors.