A Robust Type-Ii N-Graphyne/Gase Heterostructure with High Carrier Mobility Under Electric Field and Strain

Abstract

The graphyne-based two-dimensional heterostructures have exhibited great potential in the fields of electronic and optoelectronic devices. Herein, a novel vertical N-graphyne/GaSe heterostructure is constructed and its electronic and interfacial properties in terms of band structure, density of states, electrostatic potential, charge density difference, wave functions, carrier mobility, band alignment and optical absorption are comprehensively performed. The N-graphyne/GaSe heterostructure possesses an intrinsic type-II band alignment, super-high carrier mobility (10 4 cm 2 V -1 s -1 ) and strong optical absorption (10 4 ~10 5 cm -1 ) from the visible to ultraviolet light region. Particularly, the type-II band alignment in N-graphyne/GaSe heterostructure is robust against external electric field and strain. Further study reveals that the photoelectric conversion efficiency of the N-graphyne/GaSe heterostructure is vastly improved under a negative electric field and reaches up to 25.09%. The N-graphyne/GaSe heterostructure with robust type-II band alignment and high carrier mobility opens the possibility of designing of graphyne-based advanced electronic devices especially in solar cells.

Keywords: heterostructure, Electronic properties, Interfacial properties, External electric field and strain