The effects of lithographic residues and humidity on graphene field effect devices

Recently, unknown-manner changes in charge neutrality point (CNP) positioning were ascribed to humidity at graphene field effect transistors (GFETs). While the exact means of humidity interacting with hydrophobic graphene remains unknown, this work examines pristine and lithographic-process-applied graphene surfaces with surface enhanced Raman spectra (SERS). SERS analysis shows that the lithographic-process-applied graphene does not have the same properties as those of pristine graphene. Furthermore, this study has experimentally investigated the effect of humidity on the transfer characteristics of GFET and proposed a model to explain the formation of asymmetric IDS-Vbg branches in accordance with the SERS results and humidity responses.