GRAPHENE NANOSTUCTURING WITH THE HELIUM ION MICROSCOPE

Abstract

NANO-ENGINEERING OF GRAPHENE HAS ATTRACTED TREMENDOUS INTEREST FOR GRAPHENE?S POTENTIAL APPLICATIONS. HOWEVER, THE CONVENTIONAL FABRICATION TECHNIQUES, ARE EITHER LIMITED BY THE LITHOGRAPHIC RESOLUTION OR LIMITED TO FIXED GEOMETRIES. OUR GROUP HAS DEMONSTRATED A RESIST-FREE DIRECT PATTERNING METHOD TO MAKE SUB-10-NM ARBITRARY FEATURES ON GRAPHENE USING FOCUSED-HELIUM-ION-BEAM ON BOTH SUPPORTED AND SUSPENDED GRAPHENE FLAKES. HOWEVER, THIS METHOD REQUIRES A HIGH FLUENCE OF INCIDENT HELIUM IONS WHICH CAUSES SIGNIFICANT DAMAGE TO THE GRAPHENE DUE TO THE BACKSCATTERED IONS, AND WILL DEGRADE THE PROPERTIES OF THE NANOSCALE-PATTERED GRAPHENE.

BY LOCALLY DAMAGING GRAPHENE USING A RELATIVELY LOWER HELIUM ION DOSE INSTEAD OF DIRECT SPUTTERING, WE CAN UTILIZE THE DIFFERENTIAL ETCHING OF ATOMIC-HYDROGEN TO SELECTIVELY REMOVE THE DAMAGED AREA TO FABRICATE ARBITRARY NANOSCALE FEATURES ON GRAPHENE, WHILE MITIGATING THE BACKSCATTERED-ION-INDUCED DAMAGE. RAMAN CHARACTERIZATION SHOWS NO DAMAGE IS CAU