Outstandingly high thermal conductivity, elastic modulus, carrier mobility and piezoelectricity in two-dimensional semiconducting CrC₂N₄

a first-principles study

authored by

Bohayra Mortazavi, Fazel Shojaei, Brahmanandam Javvaji, Timon Rabczuk, Xiaoying Zhuang

Abstract

Experimental realization of single-layer MoSi₂N₄ is among the latest groundbreaking advances in the field of two-dimensional (2D) materials. Inspired by this accomplishment, herein we conduct first-principles calculations to explore the stability of MC₂N₄ (M = Cr, Mo, W, V, Nb, Ta, Ti, Zr, Hf) monolayers. Acquired results confirm the desirable thermal, dynamical, and mechanical stability of MC₂N₄ (M = Cr, Mo, W, V) nanosheets. Interestingly, CrC₂N₄, MoC₂N₄, and WC₂N₄ monolayers are found to be semiconductors with band gaps of 2.32, 2.76, and 2.86 eV, respectively, using the HSE06 functional, whereas VC₂N₄ lattice shows a metallic nature. The direct gap semiconducting nature of the CrC₂N₄ monolayer results in excellent absorption of visible light. The elastic modulus and tensile strength of the CrC₂N₄ nanosheet are predicted to be remarkably high, 676 and 54.8 GPa, respectively. On the basis of iterative solutions of the Boltzmann transport equation, the room temperature lattice thermal conductivity of the CrC₂N₄ monolayer is predicted to be 350 W/mK, among the highest in 2D semiconductors. CrC₂N₄ and WC₂N₄ lattices are also found to exhibit outstandingly high piezoelectric coefficients. This study introduces the CrC₂N₄ nanosheet as a novel 2D semiconductor with outstandingly high mechanical strength, thermal conductivity, carrier mobility, and piezoelectric coefficient.

Organisation(s)

PhoenixD: Photonics, Optics, and Engineering - Innovation Across Disciplines
Institute of Photonics

External Organisation(s)

Persian Gulf University
Tongji University

Type

Article

Journal

Materials Today Energy

Volume

22

Publication date

12.2021

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Renewable Energy, Sustainability and the Environment, Materials Science (miscellaneous), Nuclear Energy and Engineering, Fuel Technology, Energy Engineering and Power Technology

Sustainable Development Goals

SDG 7 - Affordable and Clean Energy

Electronic version(s)

https://doi.org/10.48550/arXiv.2108.12808 (Access: Open)
https://doi.org/10.1016/j.mtener.2021.100839 (Access: Closed)