Copper(i) sulfide: a two-dimensional semiconductor with superior oxidation resistance and high carrier mobility

Yu Guo, Qisheng Wu, Yunhai Li, Ning Lu, Keke Mao, Yizhen Bai, Jijun Zhao, Jinlan Wang, Xiao Cheng Zeng

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Two-dimensional (2D) semiconductors with suitable direct band gaps, high carrier mobility, and excellent open-air stability are especially desirable for material applications. Herein, we show theoretical evidence of a new phase of a copper(i) sulfide (Cu 2 S) monolayer, denoted δ-Cu 2 S, with both novel electronic properties and superior oxidation resistance. We find that both monolayer and bilayer δ-Cu 2 S have much lower formation energy than the known β-Cu 2 S phase. Given that β-Cu 2 S sheets have been recently synthesized in the laboratory (Adv. Mater.2016, 28, 8271), the higher stability of δ-Cu 2 S than that of β-Cu 2 S sheets suggests a high possibility of experimental realization of δ-Cu 2 S. Stability analysis indicates that δ-Cu 2 S is dynamically and thermally stable. Notably, δ-Cu 2 S exhibits superior oxidation resistance, due to the high activation energy of 1.98 eV for the chemisorption of O 2 on δ-Cu 2 S. On its electronic properties, δ-Cu 2 S is a semiconductor with a modest direct band gap (1.26 eV) and an ultrahigh electron mobility of up to 6880 cm 2 V −1 s −1 , about 27 times that (246 cm 2 V −1 s −1 ) of the β-Cu 2 S bilayer. The marked difference between the electron and hole mobilities of δ-Cu 2 S suggests easy separation of electrons and holes for solar energy conversion. Combination of these novel properties makes δ-Cu 2 S a promising 2D material for future applications in electronics and optoelectronics with high thermal and chemical stability.

Original languageEnglish (US)
Pages (from-to)223-230
Number of pages8
JournalNanoscale Horizons
Volume4
Issue number1
DOIs
StatePublished - Jan 2019

ASJC Scopus subject areas

  • Materials Science(all)

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