Multilayer C2N: Effect of Stacking Order and Number of Layers on Bandgap and Its Controlled Electronic Properties by External Electric Field

TL;DR

This study investigates how stacking order, number of layers, and external electric fields influence the electronic properties and bandgap of layered C2N, revealing tunable electronic characteristics for potential nanoscale device applications.

Contribution

It provides an ab initio analysis of multilayer C2N, showing how layer number and electric field control bandgap transitions, including a semiconductor-semimetal transition in five-layer C2N.

Findings

Band gaps decrease with increasing layers.

A direct-to-indirect bandgap transition occurs at bulk C2N.

Electric fields can tune bandgap and induce semiconductor-semimetal transition.

Abstract

Successful synthesis of the nitrogenated holey two-dimensional structures C2N (Nat. Commun. 2015, 6, 1-7) using simply wet-chemical reaction offer a cost-effective way to generate other 2D materials with novel optical and electronic properties. Using the few-layer C2N as models, we have performed an ab initio study of electronic properties of layered C2N. Band gaps of this system exhibit monotone decreasing as the number of layers increase. And a direct-gap to indirect-gap transition at the bulk C2N. Besides, when we apply an out-of-plane electric field on few-layer C2N, the band gap of multilayer C2N will be decreased as the electric field increased and a semiconductor-semimetal transition will happen for five-layer C2N under an appropriate electric field, whereas the band gap of monolayer C2N is unchanged under electric field. Owing to their tunable bandgaps in a wide range, layers C2N will have tremendous opportunities to be applied in nanoscale electronic and optoelectronic devices.