Spectroscopic studies of the physical origin of environmental aging effects on doped graphene

Abstract

The environmental aging effect of doped graphene is investigated as a function of the organic doping species, humidity, and the number of graphene layers adjacent to the dopant by studies of the Raman spectroscopy, x-ray and ultraviolet photoelectron spectroscopy, scanning electron microscopy, infrared spectroscopy, and electrical transport measurements. It is found that higher humidity and structural defects induce faster degradation in doped graphene. Detailed analysis of the spectroscopic data suggest that the physical origin of the aging effect is associated with the continuing reaction of H 2 O molecules with the hygroscopic organic dopants, which leads to formation of excess chemical bonds, reduction in the doped graphene carrier density, and proliferation of damages from the graphene grain boundaries. These environmental aging effects are further shown to be significantly mitigated by added graphene layers.

Enhanced Thermopower of Saturated Molecules by Noncovalent Anchor‐Induced Electron Doping of Single‐Layer Graphene Electrode

“…The bare graphene exhibited V CNP > 0, which was indicative of p-type doping (Figure 4a). This is due to the long exposure time in the air, [40,[60][61][62] doping by water molecules during copper etch and wet transfer processes, [63][64][65][66] and back-gate in FET measurements. [67,68] The observed p-doping was consistent with the result of Raman spectroscopy analysis.…”

Polymer-Compatible Low-Temperature Plasma-Enhanced Chemical Vapor Deposition of Graphene on Electroplated Cu for Flexible Hybrid Electronics

“…The clear contribution from the sp 2 carbon bond (∼284.3 eV) further confirmed graphene coverage on Cu, while the presence of the CO bond (∼288 eV) could be due to exposure to ambient environment. 27 Compared to the as-received Cu substrate (Figure S7a), the Cu 2p region scans indicated that the PECVD graphene growth process also removed Cu oxides, as shown in Figure 5, similar to the Cu substrate etched with dilute H 2 SO 4 (Figure S7b). We further note a blue shift in the CC component of Figure 4a for graphene grown under the condition of H 2 /CH 4 = 1, which may be attributed to the highest defect density of this sample (according to Raman spectroscopic studies) that led to less ideal sp 2 bonding and the formation of sp 3 bonds around defects.…”

Investigation of electronic properties of chemical vapor deposition grown single layer graphene via doping of thin transparent conductive films

“…Change in I 2D / I G ratio indicates that the carrier concentration of CVD grown SLG increases after PEDOT:PSS doping, a similar result have been reported previously. 37 As shown in Fig. 2c , we have plotted peak intensity ratio of D and G peaks ( I D / I G ) as function of concentration of PEDOT:PSS on graphene.…”