Tuning the graphene work function by uniaxial strain

Abstract

Forming good metal/graphene contact is of significance in making graphene devices, while tuning the graphene work function is a valid approach to decrease the contact barrier and then achieve electrodes with low contact resistance. A strain device has been fabricated to apply uniaxial strain to graphene grown by chemical vapor deposition method, and Kelvin probe force microscopy was used to measure the work function of the graphene under strain. The work function of the graphene is found to increase as strain increases. By applying a uniaxial strain of 7%, the work function can be adjusted as large as 0.161 eV. Such a result can be explained by strain induced increase of the density of states in graphene.