Thermal reversibility in electrical characteristics of ultraviolet/ozone-treated graphene

Abstract

Changes in electrical properties of a bilayer graphene-based field-effect transistor (G-FET) after being oxidized through ultraviolet (UV)/ozone (O3) treatment are presented. A decrease in conductivity and carrier mobility was observed after oxidation. However, electrical properties recovered after annealing oxidized G-FET with H2/Ar, indicating that oxidation with UV/O3 treatment was thermally reversible. Raman spectroscopy was conducted to verify that no defects were introduced after oxidation. The existence of chemical bonds between oxygen and graphene was confirmed from the X-ray photoelectron spectroscopy. Moreover, we found that graphene's sheet resistance increased after oxidation. Nevertheless, contact resistivity at graphene-Au/TiN electrode interface remained unchanged.

Imaging molecular adsorption and desorption dynamics on graphene using terahertz emission spectroscopy

“…Before introducing gases, we kept the sample in a vacuum of 10 −5 Torr. In all cases, after 10 minutes of THz emission measurement (Region I), we illuminated the sample by ultraviolet (UV) light (365 nm) for 5 minutes (Region II), motivated by the idea that UV illumination promotes oxidation of graphene 10 11 12 13 . In Region I, the THz waveforms from all samples are unchanged in different environmental gases and show similar characteristics, i.e., only the first peak can be seen.…”

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.…”

Ultraviolet-Ozone Treatment for Effectively Removing Adhesive Residue on Graphene

“…This is due to UVO may cause some damage to graphene electronic structure, and bring some p-type doping in graphene. [30][31][32][33][34] In summary, UVO treatment is a quick and easy way to remove PVA sacri¯cial polymer layer.…”

“…24 Apparently, the graphene samples hardly su®er any damage in¯rst 10 min, but after 10 min, the lattice structure of graphene is more and more disordered (the rise of D/G ratio). 30,31 Accordingly, the optimal time is chose to be 10 min.…”