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 currentvoltage characteristics.

Improving the electrical properties of graphene layers by chemical doping

“…It is already reported that the shift of the G and 2D peaks positions toward lower wavenumbers is attributed to n-type doping [34, 40, 44, 45], and the shift of the G and 2D peaks positions toward higher wavenumbers is attributed to p-type doping in graphene layers [46–48]. Figure 2(a) shows the Raman spectra of pristine and KNO 3 -doped SLG.…”

Substrate-dependent resistance decrease of graphene by ultraviolet-ozone charge doping

“…Unfortunately, almost all of the experimental studies show that the sheet resistance of the UVO treated graphene is several orders of magnitude higher than pristine graphene, reaching MΩ or GΩ regimes, which can be viewed as a metal-insulator transition (see the summarized references in Table S1). [28][29][30][31][32][33][34][35][36] Very recently, there are several reports providing some interesting results indicating that the resistance of graphene can be decreased by using UVO treatment on the traditional SiO 2 substrate. [37][38][39] Most of the researches focus on the effect of graphene on SiO 2 substrate or the wavelength of the utilized UV light for generation ozone molecules.…”

Effect of doping on photovoltaic characteristics of graphene

“…These results confirm that the graphene investigated in this study is high-quality single layer. [21] It is already reported that the shift of the G and 2D peaks positions toward lower wavenumbers is attributed to n-type doping [22,23], and the shift of the G and 2D peaks positions toward higher wavenumbers is attributed to p-type doping in graphene layers [24][25][26]. Figure 2a shows the Raman spectra of pristine and PTSA doped single layer graphene.…”