First-principles study of graphene intercalation in h-BN based resistance random access memory

Abstract

Graphene intercalation between metal electrode and resistance layers has attracted extensive experimental and theoretical research because of its capability to manipulate the electronic structure and properties of hexagonal boron nitride based resistance random access memory. Herein, the interface characteristic, adsorption and migration behavior of Ti on pristine and defective graphene intercalation have been systematically investigated by utilizing the density functional theory method, which could help accurately preset defects and regulate the permeation process. Analysis of the interfacial contact form showed that Ohmic-type contact occurs between intercalation and resistance layer interface due to the heavy doping effect caused by charge accumulation on the h-BN layer surface upon introduction of intercalation. Ti metal adsorption at hollow site on defective graphene containing grain boundary with double vacancies was more energetically favorable than that on pristine graphene without vacancy or with single vacancy, whereas the increase of adsorption energy caused by grain boundary defects that represented by pentagons and heptagons and double vacancies were very limited. Migration barrier calculations with defect distribution and vacancy indicated that the critical factor controlling ion penetration in the whole intercalation process is the presetting of single vacancy defect rather than the varying number of vacancies and the existence of grain boundary defect. This finding provides a new perspective aiding understanding and design of the defect-assisted graphene intercalation mechanism.