Electrical and optical behaviors of SiC(GeC)/MoS 2 heterostructures: a first principles study

Eur. Phys. J. Appl. Phys.

2018

n-Type contact of Schottky barriers at two-dimensional (2D) materials/metal interfaces is a usual formalization in the modern FETs applications. It is common to modulate it from n-to p-type through some specific methods. In this work, we came up with two new intrinsic p-type contacts of graphene-GeC/GeS and further tune them from p-type to n-type by external electric fields. It proved that the electronic properties of graphene and GeC/GeS can be roughly preserved for the weak van der Waals (vdW) interaction. p-Type contacts with relatively small barriers are formed at g-GeC/GeS heterointerfaces. After external electric field applied, the Schottky barrier can be effectively tuned by different external electric and the p-type contact further turns into n-type. Variation of the Schottky barriers indicated a partial pinning for interfaces of g-GeC/GeS. This is because the interfacial states between graphene and GeC/GeS hardly exists. The barrier height of g-GeC/GeS and the corresponding contact type can be flexibly tuned, which is of great importance in the design of novel transistors-based 2D materials. Searching for novel nanoscale electronic equipment based on 2D materials is a hot topic in the current study. This work would provide meaningful guidelines for nanoscale devices.*

Section: Resultssupporting

confidence: 87%

“…This is mainly due to the positive transverse acoustic mode Grüneisen parameters. Rao et al [24] further calculated the electrical and optical behaviors of GeC/ MoS 2 heterostructure. Noncovalent bonding exists between the junctions due to the weak orbital coupling.…”

Section: Introductionmentioning

confidence: 99%

The modulation of Schottky contacts of p-type graphene-GeC/GeS heterointerface

Cui

Eur. Phys. J. Appl. Phys.

2018

“…In structural optimization process, the cell parameters are fixed while ionic positions are fully relaxed with k-point mesh of 5 Â 5 Â 1 generated based on Monkhorst and Pack scheme and 10 À5 eV energy convergence criteria. The optimized parameters including bond angles and atomic distances for stand-along BP/GeX meet well with previous results, ensuring the credibility of the above approach [24][25][26][27]. The above structures are further optimized until the forces on each atom are less than 0.01 eV/Å.…”

Section: Introductionsupporting

confidence: 71%

The strain induced type-II band re-alignment of blue phosphorus-GeX (X = C/H/Se) heterostructures

Cui

Eur. Phys. J. Appl. Phys.

et al. 2020

Efforts to efficiently use of the next generation 2-dimension (2D) structured monolayers is getting a lot of attention for their excellent properties recently. In this work, we composite the blue phosphorus (BP) and monolayer GeX (X = C/H/Se) via van der Waals force (vdW) interaction to obtain well defined type-II band alignment heterostructures. A systematic theoretic study is conducted to explore the interlayer coupling effects and the bands re-alignment of BP-GeX (X = C/H/Se) heterostructure after the strain imposed. To devise usable and efficient materials to degrade pollutant or used as a potential photovoltaic cell material, previous researches have proved that using 2D materials as components is a feasible way to obtain high performance. Here, we prudently present a comprehensive investigation on the BP and GeX (X = C/H/Se) with different twisted angles via first-principles calculation to lay a theoretical framework on the band alignment and carriers' separation. It reveals that the intrinsic electronic properties of BP and GeX are roughly preserved in the corresponding heterostructures. Upon strain applied, band alignment can be flexibly manipulated by varying external imposed strain. The heterostructures can maintain type-II character within a certain strain range, and thus the carriers are spatially separated to different portions. This work not only provides a deep insight into the construction of the heterostructure, but presents a new possibility to search for a flexible and feasible approach to promote its catalytic performance. The corresponding results would provide meaningful guidelines for designing 2D structure based novel materials.

“…Shi et al studied the electronic properties of the GeC/WS 2 heterostructure under an electric field (E-field) and modulated its bandgap [26]. Rao et al studied SiC(GeC)/MoS 2 heterostructures and found enhanced optical absorption [27] and their results are promising for applications in field-effect transistors. To the best of our knowledge, the studies on the tunable electronic properties of heterostructures containing SiC and GeC are still lacking.…”

Section: Introductionmentioning

confidence: 99%

Tuning Electronic Properties of the SiC-GeC Bilayer by External Electric Field: A First-Principles Study

2019

Micromachines

First-principles calculations were used to investigate the electronic properties of the SiC/GeC nanosheet (the thickness was about 8 Å). With no electric field (E-field), the SiC/GeC nanosheet was shown to have a direct bandgap of 1.90 eV. In the band structure, the valence band of the SiC/GeC nanosheet was mainly made up of C-p, while the conduction band was mainly made up of C-p, Si-p, and Ge-p, respectively. Application of the E-field to the SiC/GeC nanosheet was found to facilitate modulation of the bandgap, regularly reducing it to zero, which was linked to the direction and strength of the E-field. The major bandgap modulation was attributed to the migration of C-p, Si-p, and Ge-p orbitals around the Fermi level. Our conclusions might give some theoretical guidance for the development and application of the SiC/GeC nanosheet.