Bandgap engineering in aperiodic Thue-Morse graphene superlattices

E A Carrillo-Delgado,L M Gaggero-Sager,I Rodríguez-Vargas

doi:10.1063/1.5081750

Abstract

The lack of bandgap in graphene is the main factor that prevents that this outstanding material be implemented in optoelectronics. In this work, we show that by nanostructuring graphene aperiodically it is possible to have an efficient transmission bandgap engineering. In particular, we are considering aperiodic graphene superlattices in which electrostatic barriers are arranged following the basic construction rules of the Thue-Morse sequence. We find that the transmission bandgap can be modulated readily by changing the angle of incidence as well as by appropriately choosing the generation of the Thue-Morse superlattice. Even, this angle-dependent bandgap engineering is more effective than the corresponding one for periodic graphene superlattices.

Highlights

Graphene1,2 is a material with surprising and unique properties that no other material offers, to such degree, that it is regarded as a miracle material
We propose a bandgap engineering based on the angular dependence of the propagation of Dirac electrons in aperiodic Thue-Morse graphene superlattices (TM-GSLs)
In order to unveil the fundamental differences between the angle-dependent bandgap engineering of aperiodic and periodic graphene superlattices we will calculate the transmission properties of TM-GSLs for specific generations and the corresponding ones for Periodic-GSLs, taking care that number of barriers in both systems be the same

Summary

INTRODUCTION

Graphene is a material with surprising and unique properties that no other material offers, to such degree, that it is regarded as a miracle material. Despite the advances in the control of ribbon edges, the size of the bandgap (∼ 100 meV) as well as the mass production of reliable nanoribbons are the main obstacles of this proposal Another possibility is to induced a bandgap via the interaction of graphene with substrates like SiC or hBN, in the range of 50 to 260 meV.. We can think in an angle-dependent bandgap engineering in gated graphene superlattices.17 In this case, the bandgap can be tuned by modulating the angle of the incident electrons. The highly anisotropic propagation of charge carriers in graphene and aperiodicity open the possibility for an angle dependent aperiodic bandgap engineering. We propose a bandgap engineering based on the angular dependence of the propagation of Dirac electrons in aperiodic Thue-Morse graphene superlattices (TM-GSLs). This angle-dependent bandgap engineering is more effective than the corresponding one for periodic graphene superlattices (Periodic-GSLs).

MODEL AND METHOD

RESULTS

CONCLUSIONS