Formation of p–n junction with stable p-doping in graphene field effect transistors using deep UV irradiation

Abstract

We demonstrate the modification of the electronic properties of single layer chemical vapor deposition (CVD)-grown graphene by deep ultraviolet (DUV) light irradiation. The shift in the G and 2D bands in Raman spectra towards higher wavenumber suggests p-doping in graphene field effect transistors (FETs). In the transport measurements, the Dirac point is shifted towards positive gate voltage with increasing DUV light exposure time, revealing the strong p-doping effect without a large resistance increase. The doping is found to be stable in graphene devices, with a slight change in mobilities. We also constructed a p–n junction by DUV light exposure on selected regions of graphene, and investigated it with gate voltage dependent resistivity measurements and current–voltage characteristics.