Layer-dependent electronic properties of phosphorene-like materials and phosphorene-based van der Waals heterostructures

Abstract

Black phosphorus is a layered semiconducting allotrope of phosphorus with high carrier mobility. Its monolayer form, phosphorene, is an extremely fashionable two-dimensional material which has promising potential in transistors, optoelectronics and electronics. However, phosphorene-like analogues, especially phosphorene-based heterostructures and their layer-controlled electronic properties, are rarely systematically investigated. In this paper, the layer-dependent structural and electronic properties of phosphorene-like materials, i.e., mono- and few-layer MXs (M = Sn, Ge; X = S, Se), are first studied via first-principles calculations, and then the band edge position of these MXs as well as mono- and few-layer phosphorene are aligned. It is revealed that van der Waals heterostructures with a Moiré superstructure formed by mutual coupling among MXs and among MXs and few-layer phosphorene are able to show type-I or type-II characteristics and a I-II or II-I transition can be induced by adjusting the number of layers. Our work is expected to yield a new family of phosphorene-based semiconductor heterostructures with tunable electronic properties through altering the number of layers of the composite.

Tuning the Carrier Confinement in GeS/Phosphorene van der Waals Heterostructures

“…Recalling our previous thoughts that altering the number of layer of the composites might confine the carriers within different components, i.e., transition into the type‐II alignment, we further computed the band edge positions of GeS bilayer . As can be seen in Figure , the VBM energy of 2L‐GeS is slightly upraised by 30 meV with respect to 1L‐GeS, while the CBM energy is driven down by about 160 meV.…”

“…Naturally, one could anticipate that vdW heterostructure based on phosphorene would be extremely interesting, not only because the heterostructures would inherit and further develop the excellent properties of phosphorene, but also would largely enrich the research area of phosphorene‐based science. Recently, phosphorene‐based heterostructures have indeed attracted a great deal of attention . For example, a gate‐tunable p–n diode based on a p‐type phosphorene/n‐type MoS 2 monolayer has been reported to show a promising prospect for broadband photodetection and solar energy harvesting with a maximum photodetection responsivity of 418 mA W −1 .…”

“…In particular, the role of phosphorene in the next‐generation photovoltaics cells is delineated and prospected in detail . Within the framework of density functional theory (DFT) calculations, our group have exploited the electronic properties of vdW heterostructures formed by phosphorene coupled with phosphorene‐like analogues and demonstrated that the transition from a type‐II to type‐I or a type‐I to type‐II alignment could be realized by tuning the number of layers of the composite . Note that the type‐II heterostructures, where the valence band maximum (VBM) and conduction band minimum (CBM) belong to two independent layers, can result in the photogenerated electrons and holes being spatially separated .…”

“…As a typical IV–VI semiconductor, GeS can be crystallized into a phosphorene‐like structure. Previous studies have demonstrated the electronic property of GeS is sensitive to the number of layer . Thus, it is of great interest to explore the electronic properties of hybrid structure made of GeS and phosphorene with common layer‐dependent features, which would produce charming properties that differ from their single material, thereby extending the possibilities for other potential applications.…”

SnSe/MoS2 van der Waals Heterostructure Junction Field‐Effect Transistors with Nearly Ideal Subthreshold Slope

“…The multilayer SnSe and MoS 2 has bandgap of 1.0 eV [27] and 1.2 eV, [28] respectively, although SnSe has lower electron affinity compared to MoS 2 ( Figure 1d). Considering multilayer SnSe and multilayer MoS 2 is unintentionally p-type and n-type doped (See Figure S1a,b in the Supporting Information, transfer curves of MoS 2 and SnSe FET, the low ON/OFF ratio of Figure S1b (Supporting Information) is due to thick body and electric field screening effect) and their fermi energy is close to their valance band [29] and conduction band, [30,31] respectively, a p-n heterojunction forms at the SnSe/MoS 2 vdW interface.…”