A Facile Route To Recover Intrinsic Graphene over Large Scale

Abstract

The intrinsic properties of initially p-type doped graphene (grown by chemical vapor deposition (CVD)) can be recovered by buffered oxide etch (BOE) treatment, and the dominant factor governing p-type doping is identified as the H(2)O/O(2) redox system. Semi-ionic C-F bonding prevents the reaction between the products of the H(2)O/O(2) redox system and graphene. BOE-treated graphene field effect transistors (FETs) subsequently exposed to air, became p-type doped due to recovery of the H(2)O/O(2) redox system. In comparison, poly(methyl methacrylate) (PMMA)-coated graphene FETs had improved stability for maintaining the intrinsic graphene electronic properties.

Hydroxyl-free buffered dielectric for graphene field-effect transistors

“…This may indicate that there is no reaction between graphene and BCB during the curing process. The chemical structure of the BCB polymer does not contain any notable polarized groups such as hydroxyl groups with p-doping in graphene or amine groups with n-doping [15,22,23], the left shift of Dirac voltage is mainly attributed to the remove of the adsorbates on graphene, especially H 2 O and O 2 molecules as p-dopants, by heating treatment at high temperature, rather than effects of the BCB polymer itself [35][36][37][38][39]. The following deposition of Al 2 O 3 changes the graphene flake to nearly intrinsic properties (V BG, Dirac = À3 V).…”

Chemical-sensitive graphene modulator with a memory effect for internet-of-things applications

“…There are several ways to restore the intrinsic electrical characteristics and tune the V cnp of graphene; these include (1) high-vacuum annealing or high-temperature heating, which causes the desorption of the substances on the graphene 1,24 , and (2) wet chemical treatment, although most studies of this method are based on photoresist-contaminated GFETs and the recovery chemicals involved are hazardous (BOE, HF, and CHCl 3 ) 25,35 . In this study, ethanol treatment could serve as a cost-effective, non-toxic and ecofriendly method of resetting the V cnp of a photoresist-free GFET.…”

“…This interesting feature could be advantageous for continuous-time biomedical and environmental monitoring, considering that the calibration of the memory effect on site is regarded as an important issue for practical applications in long-period and multicycle sensing. Thus far, several methods of tuning V cnp , on which the modulated output signal depends, have been reported, including annealing the device under high vacuum, post-heating at high temperature, and applying a specialized gas/wet treatment after the adsorption of substances onto the graphene 1,3,24,25 . However, these calibration methods require extreme conditions to initiate the memory effect in the graphene and thus are not feasible for pervasive sensing or continuous monitoring applications.…”

Characterization of N-doped multilayer graphene grown on 4H-SiC (0001)

“…However once the device is pumped down to 10 -5 mbar the VD shifts down to -1V and the device clearly reveals the n-type doping character of N incorporation of the graphene 22 . Graphene exposed to air tends to be p-type doped due to its interaction with the H2O/O2 so pumping break those bonding and brings graphene back to its intrinsic VDirac 24 . This top gate FET exhibits interesting room temperature mobilities of 1350 cm²/Vs and 850 cm²/Vs for hole and electron respectively.…”