Unusual Mechanism Behind Enhanced Photocatalytic Activity and Surface Passivation of SiC(0001) via Forming Heterostructure with a MoS₂ Monolayer

Abstract

A two-dimensional (2D)/three-dimensional (3D) hybrid heterostructure has recently emerged as an effective method for improving photocatalytic efficiency. In this work, we perform a comprehensive first-principles study of the structural, electronic, and optical properties of a novel 3D-SiC/2D-MoS 2 heterostructure. The calculation results reveal that the SiC(0001) surface/MoS 2 monolayerintegrated heterostructure in Schottky contact with a new chemical bonding contributed to the surface adhesion and optoelectronic properties. Meanwhile, the valence and conduction band-edge positions of SiC and MoS 2 changed with the Fermi level and formed a desired type-II band alignment, which greatly facilitate the rapid separation of photogenerated carriers. Moreover, the surface state of SiC(0001) can be removed when combined with MoS 2 , and their band gap is also reduced. Furthermore, Bader charge and charge density difference indicated that there is a remarkable separated distribution of electrons and holes at the interface. These results demonstrated that the band structure of the 3D-SiC/2D-MoS 2 heterostructure had significant advantages to improve the photocatalytic efficiency under visible-light irradiation.

High-k Monolayer CaF2 as the Gate Dielectric for Two-Dimensional SiC-Based Field-Effect Transistors

“…The equilibrium interlayer distances of the two patterns are 3.19 and 3.65 Å (also listed in Table ), respectively. The interlayer spacing values are in the range of previously reported values for vdW systems (i.e., about 2.5–3.8 Å), , which indicates that both 2D SiC/CaF 2 and 2D SiC/hBN interfaces are dominated by weak vdW force interactions.…”

Modulating the Schottky barrier of MXenes/2D SiC contacts via functional groups and biaxial strain: a first-principles study

“…, about 2.5–3.5 Å). 36,37 It is inferred that the Ti 3 C 2 O 2 /SiC (A) contact has a strong interlayer interaction. In addition, the hybridization of SiC states is remarkable and the SiC band gap disappears, as seen in the PDOS of SiC in Ti 3 C 2 O 2 /SiC (A), indicating the metallization of SiC (see Fig.…”

“…16 By comparing the E b values, the The corresponding interfacial distance is calculated to be 1.851Å (see Table 1), which is close to the bond length of Si-O but much shorter than previously reported values for vdW systems (i.e., about 2.5-3.5 Å). 36,37 It is inferred that the Ti To measure the electron localization and characterize the physical bonds in the molecular and solid-state systems, the corresponding ELFs of the Ti 3 C 2 F 2 /SiC, Ti 3 C 2 O 2 /SiC and Ti 3 C 2 (OH) 2 /SiC contacts are calculated as shown in Fig. 2(d-f), respectively.…”

Recent progress of heterostructures based on two dimensional materials and wide bandgap semiconductors

“…Heterostructures of 2D materials and SiC, with type II energy band arrangement such as MoS2/SiC and boron phosphide/SiC, can separate electrons and holes at the interface more efficiently, making them excellent candidates for photocatalysts. [110,111] Mathur et al proposed a new method to modulate photocatalytic activity and band gap narrowing in EG/SiC (6H-SiC and 3C-SiC) to produce efficient photocatalysts. [112] The photocatalytic reaction rate for EG/6H-SiC composites were improved by ~1000% under UV light, and the bandgap was narrowed to 2 eV or even smaller under the visible light with a tunable quality factor I2D/IG.…”

“…Currently, the low separation efficiency and mobility of photogenerated carriers are the main limitations of photocatalysis. Heterostructures of 2D materials and SiC, with type II energy band arrangement such as MoS 2 /SiC and boron phosphide/SiC, can separate electrons and holes at the interface more efficiently, making them excellent candidates for photocatalysts [110,111].…”