Charge transport in lightly reduced graphene oxide: A transport energy perspective

Kajen, R. S.; Chandrasekhar, N.; Pey, K. L.; Vijila, C.; Jaiswal, Manu; Saravanan, S.; Ng, Andrew Keong; Wong, C. P.; Loh, Kian Ping

doi:10.1063/1.4792042

Cited by 22 publications

(17 citation statements)

References 30 publications

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“…From the Arrhenius plot at a high temperature regime (above 220 K), as shown in the inset of Figure 3b, it yields the E a value of ∼70.2 meV which is relatively higher compared to the previously reported values for N-doped graphene 13 and rGO. 44,45 Generally, graphene with less structural defects or impurities would give low E a as it is much easier for the electrons to be excited from the VB to the conduction band (CB) at room temperature. However, in our case, the higher E a in the N-rGO would be attributed to the existence of structural defects and disorders in the carbon network, consistent with the findings from Raman spectra (see Figure S4) and N 1s peak of XPS (see Figure 2).…”

Section: Resultsmentioning

confidence: 99%

Wafer-Scale Fabrication of Nitrogen-Doped Reduced Graphene Oxide with Enhanced Quaternary-N for High-Performance Photodetection

Haniff

Ariffin

Hafiz

et al. 2019

ACS Appl. Mater. Interfaces

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We demonstrated a simple and scalable fabrication route of a nitrogen-doped reduced graphene oxide (N-rGO) photodetector on an 8 in. wafer-scale. The N-rGO was prepared through in situ plasma treatment in an acetylene-ammonia atmosphere to achieve an n-type semiconductor with substantial formation of quaternary-N substituted into the graphene lattice. The morphology, structural, chemical composition, and electrical properties of the N-rGO were carefully characterized and used for the device fabrication. The N-rGO devices were fabricated in a simple metal−semiconductor−metal structure with unconventional metal-on-bottom configuration to promote high-performance photodetection. The N-rGO devices exhibited enhanced photoresponsivity as high as 0.68 A W −1 at 1.0 V, which is about 2 orders of magnitude higher compared to a pristine graphene and wide-band photoinduced response from the visible to the near-infrared region with increasing sensitivity in the order of 785, 632.8, and 473 nm excitation wavelengths. We also further demonstrated a symmetric characteristic of the photoinduced response to any position of local laser excitation with respect to the electrodes. The excellent features of waferscale N-rGO devices suggest a promising route to merge the current silicon technology and two-dimensional materials for future optoelectronic devices.

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Section: Resultsmentioning

confidence: 99%

Wafer-Scale Fabrication of Nitrogen-Doped Reduced Graphene Oxide with Enhanced Quaternary-N for High-Performance Photodetection

Haniff

Ariffin

Hafiz

et al. 2019

ACS Appl. Mater. Interfaces

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“…As known in literature and mentioned above, a widespread defect is related to oxygen functional groups (with sp 3 hybridization), bridge-bonded to the graphene planes, supposed to create potential barriers between sp 2 hybridised crystalline and disordered regions [37,42,44,56]. It has been suggested before, that the barrier height depends on the local density of oxygen functional groups within the disordered regions and it can explain the large resistance that the VRH model predicts at low temperatures [42,44].…”

Section: Discussionmentioning

confidence: 82%

“…SEM observations and micro-analysis have revealed a morphology consisting of partially overlapped small flakes of rGO. These comprise conducting graphene-like sp 2 regions [56], as suggested by the presence of high wavenumber broader bands in the Raman spectrum (Figure 6) and by SEM analysis (Figure 3B). These sp 2 domains have a size of L a 16.3 nm, at RT, and are embedded in GO disordered regions [42,56], with a mean distance among defects of L D 11 nm at RT.…”

Section: Discussionmentioning

confidence: 90%

Electronic Transport Mechanisms Correlated to Structural Properties of a Reduced Graphene Oxide Sponge

Pinto¹,

McNaughton²,

Minicucci³

et al. 2021

Preprint

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We report morpho-structural properties and charge conduction mechanisms of a foamy “graphene sponge”, having a density as low as ≈ 0.07 kg/m3 and a carbon to oxygen ratio C:O ≃ 13:1. The spongy texture analysed by scanning electron microscopy is made of irregularly-shaped millimetres-sized small flakes, containing small crystallites with a typical size of ≃ 16.3 nm. A defect density as high as ≃ 2.6×1011 cm−2 has been estimated by the Raman intensity of D and G peaks, dominating the spectrum from room temperature down to ≃ 153 K. Despite the high C:O ratio, the graphene sponge exhibits an insulating electrical behavior, with a raise of the resistance value at ≃ 6 K up to 5 orders of magnitude with respect to the room temperature value. A variable range hopping (VRH) conduction, with a strong 2D character, dominates the charge carriers transport, from 300 K down to 20 K. At T&lt; 20 K, graphene sponge resistance tends to saturate, suggesting a temperature-independent quantum tunnelling. The 2D-VRH conduction originates from structural disorder and is consistent with hopping of charge carriers between sp2 defects in the plane, where sp3 clusters related to oxygen functional groups act as potential barriers.

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“…As known in literature and mentioned above, a widespread defect is related to oxygen functional groups (with sp 3 hybridization), bridge-bonded to the graphene planes, supposed to create potential barriers between sp 2 hybridised crystalline and disordered regions [39,44,46,57]. It has been suggested before, that the barrier height depends on the local density of oxygen functional groups within the disordered regions and it can explain the large resistance that the VRH model predicts at low temperatures [44,46].…”

Section: Discussionmentioning

confidence: 82%

“…SEM observations and micro-analysis have revealed a morphology consisting of partially overlapped small flakes of rGO. These comprise conducting graphene-like sp 2 regions [57], as suggested by the presence of high wavenumber broader bands in the Raman spectrum (Figure 6) and by SEM analysis (Figure 3B). These sp 2 domains have a size of L a 16.3 nm, at RT, and are embedded in GO disordered regions [44,57], with a mean distance among defects of L D 11 nm at RT.…”

Section: Discussionmentioning

confidence: 90%

Electronic Transport Mechanisms Correlated to Structural Properties of a Reduced Graphene Oxide Sponge

et al. 2021

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We report morpho-structural properties and charge conduction mechanisms of a foamy “graphene sponge”, having a density as low as ≈0.07 kg/m3 and a carbon to oxygen ratio C:O ≃ 13:1. The spongy texture analysed by scanning electron microscopy is made of irregularly-shaped millimetres-sized small flakes, containing small crystallites with a typical size of ≃16.3 nm. A defect density as high as ≃2.6 × 1011 cm−2 has been estimated by the Raman intensity of D and G peaks, dominating the spectrum from room temperature down to ≃153 K. Despite the high C:O ratio, the graphene sponge exhibits an insulating electrical behavior, with a raise of the resistance value at ≃6 K up to 5 orders of magnitude with respect to the room temperature value. A variable range hopping (VRH) conduction, with a strong 2D character, dominates the charge carriers transport, from 300 K down to 20 K. At T < 20 K, graphene sponge resistance tends to saturate, suggesting a temperature-independent quantum tunnelling. The 2D-VRH conduction originates from structural disorder and is consistent with hopping of charge carriers between sp2 defects in the plane, where sp3 clusters related to oxygen functional groups act as potential barriers.

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Charge transport in lightly reduced graphene oxide: A transport energy perspective

Abstract: Articles you may be interested inA detailed analysis of current-voltage characteristics of Au/perylene-monoimide/n-Si Schottky barrier diodes over a wide temperature range

Cited by 22 publications

References 30 publications

Wafer-Scale Fabrication of Nitrogen-Doped Reduced Graphene Oxide with Enhanced Quaternary-N for High-Performance Photodetection

Wafer-Scale Fabrication of Nitrogen-Doped Reduced Graphene Oxide with Enhanced Quaternary-N for High-Performance Photodetection

Electronic Transport Mechanisms Correlated to Structural Properties of a Reduced Graphene Oxide Sponge

Electronic Transport Mechanisms Correlated to Structural Properties of a Reduced Graphene Oxide Sponge

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