Search

The fabrication of two-dimensional (2D) quasi-hexagonal phase (qHP) C60 semiconductor material offers a promising candidate for high-performance electronic devices. Selecting appropriate metals is crucial for achieving Ohmic contact (OhC) to enhance carrier injection efficiency. In this Letter, we used first-principles calculations to study the contact properties of seven 2D metal/qHP C60 van der Waals heterostructures. Metals with suitable work functions can form p-type Schottky contacts (p-ShCs), n-type Schottky contacts (n-ShCs), and OhCs. Differences in work function affect interface charge transfer, creating interface dipoles and causing band alignment deviations from the ideal Schottky–Mott limit. The calculated Fermi level pinning factors for n-type and p-type 2D metal/qHP C60 vdWh are 0.528 and 0.521, respectively. By regulating Φn and Φp based on electrostatic potential difference ΔV, we have achieved the ideal Schottky–Mott limit. We also studied the Schottky barrier height of the germanene/qHP C60 vdWh, finding that using electric field is an effective way to convert n-ShC to OhC or p-ShC. These findings provide theoretical guidance for constructing efficient 2D qHP C60 electronic devices. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) ferromagnetic semiconductors with high Curie temperature (TC) and magnetic tunability have garnered significant research interest owing to their immense potential in the realm of spintronic devices. Herein, 2D Ising ferromagnetic semiconductor InMoTe3 monolayer with robust ferromagnetic coupling and TC above room temperature is predicted. Additionally, it has been shown that biaxial strain can notably affect the magnetic interactions and TC of InMoTe3 monolayer. The findings in this study suggest that InMoTe3 monolayer holds promise as a candidate for spintronic device applications, thereby encouraging further theoretical and experimental investigations in this field. [ABSTRACT FROM AUTHOR]

Recently, the newly synthesized septuple-atomic layer two-dimensional (2D) material MoSi2N4 (MSN) has attracted attention worldwide. Our work delves into the effect of vacancies and external electric fields on the electronic properties of the MSN/graphene (Gr) heterostructure using first-principles calculation. We find that four types of defective structures, N-in, N-out, Si and Mo vacancy defects of monolayer MSN and MSN/Gr heterostructure are stable in air. Moreover, vacancy defects can effectively modulate the charge transfer at the interface of the MSN/Gr heterostructure as well as the work function of the pristine monolayer MSN and MSN/Gr heterostructure. Finally, the application of an external electric field enables the dynamic switching between n-type and p-type Schottky contacts. Our work may offer the possibility of exceeding the capabilities of conventional Schottky diodes based on MSN/Gr heterostructures. [ABSTRACT FROM AUTHOR]

The emerging Janus Ga2SeTe with an asymmetric structure has attracted a great deal of research interest. In this paper, we construct the van der Waals heterostructures (vdWHs) of monolayer Janus Ga2SeTe and germanene (Ge) and named their two stacking modes as Te/Ge vdWH and Se/Ge vdWH. We find that Ge/Ga2SeTe vdWHs in both stacking modes form n-type Schottky contacts. Furthermore, the Schottky barrier height and Schottky contact type in Ge/Ga2SeTe are modulated through interlayer distances and electric fields, which lead to a transition from n-type to p-type Schottky contacts or ohmic contacts. In particular, the weak interaction between the two monolayers leads to the creation of a band gap in the Dirac cone. When a compressive strain in the z direction is applied to the Se/Ge heterostructure, Ge has a larger band gap. The results of our work can provide valuable guidance for the design of controllable Schottky nanodevices and high-performance optoelectronic devices based on Ge/Ga2SeTe vdWHs. [ABSTRACT FROM AUTHOR]

Multiferroic materials, coexisting of ferroelectric, ferromagnetic and ferroelastic properties, possess potential applications in functional devices. BiFeO3 (BFO) is a unique room temperature multiferroic material with high ferroelectric Curie temperature and Neel temperature. The BFO thin films were prepared on Si (111) substrate by sol-gel method in this paper. XRD analyses show that the thin films exhibit pure phase and preferred (100) orientation when annealing temperature is 500 °C. Field emission scanning electron microscopy shows that the crystallization degree of the films is getting better with the increase of annealing temperature. The thickness of the sample is about 400 nm. The hysteresis loop of BFO films annealing at 500 °C show 1.93 µC/cm2 remnant polarizations. However, the hysteresis loop is not perfect, which may be caused by a large leakage current. The magnetic hysteresis loop of BFO films is tested as well, indicating that the BFO film is antiferromagnetic and the residual magnetization (Mr) and coercive field (Hc) of the BFO films were 0.054 emu/g and 1026.4 Oe, respectively. [ABSTRACT FROM AUTHOR]