A novel broken-gap chemical-bonded SiC/Ti2CO2 heterojunction with band to band tunneling: first-principles investigation

Zhuo-Ni Dai; Wei Sheng; Xiao-Ying Zhou; Jie Zhan; Ying Xu

doi:10.1039/d3cp03273f

A novel broken-gap chemical-bonded SiC/Ti₂CO₂ heterojunction with band to band tunneling: first-principles investigation

Phys Chem Chem Phys. 2023 Sep 13;25(35):23954-23962. doi: 10.1039/d3cp03273f.

Authors

Zhuo-Ni Dai^{1

2}, Wei Sheng^{1

2}, Xiao-Ying Zhou^{1

2}, Jie Zhan^{1

2}, Ying Xu^{1

2}

Affiliations

¹ School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201, China. yxu@hnust.edu.cn.
² Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials, Xiangtan 411201, Hunan, China.

PMID: 37642559
DOI: 10.1039/d3cp03273f

Abstract

A broken-gap heterojunction is a bright approach for designing tunneling field-effect transistors (TFETs) due to its distinct quantum tunneling mechanisms. In this study, we investigate the electronic structure and transport characteristics of a SiC/Ti₂CO₂ heterojunction, as well as the impacts of electric field and strain on the electronic properties via density functional theory. We determine that the interfacial atoms of the heterojunction are covalently bonded, forming a type-III heterojunction with a broken-gap. There exists band-to-band tunneling (BTBT) from the valence band (VB) of SiC to the conduction band (CB) of Ti₂CO₂. The creation of the heterojunction also enhances the carrier mobility arising from the large elastic modulus and the decrease of deformation potential. The current-voltage (I-V) characteristics of the device demonstrate a pronounced negative differential resistance (NDR) effect, along with a current that is about ten times greater than that of the vdW type-III heterojunction. Moreover, the tunneling window of SiC/Ti₂CO₂ is only slightly altered when subjected to an external electric field and vertical strain, demonstrating the remarkable stability of its type-III band alignments. Our results indicate that the SiC/Ti₂CO₂ heterojunction is useful to construct high-performance TFETs, and also introduces new ideas to design TFETs by using type-III covalent-bond heterojunctions.