Hi. The simple way is do photolithography and expose to O2 plasma. If you don't have access to mask aligner to no problem, do as follows: spin coat AZ5214 resist, back at 95C for 90s, then use regular optical microscope with least intensity search for the region from where you want to remove graphene, expose to full intensity for 15s, and develop in AZ developer for 17s. You will see a hole, the expose to O2 plasma of 100w for 90s. remove the resist in hot acetone.