▎ 摘　　要

Here, a graphene nanoribbon (GNR) field-effect transistor (FET), which includes an initial electrical defect on the GNR channel, is studied via electrical transport and scanning thermal microscope (SThM) measurements. That the spatial temperature distribution for a Joule self-heated GNR FET could be directly investigated before and after the breakdown condition. This method for investigating failures in a GNR channel will allow us to diagnose the quality of nanoscale graphene.