In Situ Raman Studies of Electrically Reduced Graphene Oxide and Its Field-Emission Properties

Sahoo, Satyaprakash; Khurana, Geetika; Barik, Sujit K.; Dussan, S.; Barrionuevo, D.; Katiyar, Ram S.

doi:10.1021/jp400573w

Cited by 46 publications

(24 citation statements)

References 41 publications

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“…However, the reduction process results in unrepaired defects after the detachment of many oxygen groups, thus leading to the higher intensity of the D band. [ 54 ] A similar behavior was observed by in situ Raman spectroscopy with an elevated temperature from 93 to 773 K (Supporting Information, Figure S6). The full area is expressed with a uniform blue color, which means that the GO fi lms' G band has a relatively strong intensity compared to the D band, as confi rmed by Raman spectra (Figure 3 c and Supporting Information, Figure S5) obtained from the yellow point in Figure 3 b.…”

Section: Resultssupporting

confidence: 77%

Conductive Graphitic Channel in Graphene Oxide‐Based Memristive Devices

Kim

Jang

et al. 2016

Adv Funct Materials

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wileyonlinelibrary.comdichalcogenides (TMDs), [11][12][13] and black phosphorous, [ 14 ] have been highlighted as promising candidates. Among these materials, graphene oxide (GO) has been extensively studied to develop electronic devices based on atomically thin fi lms. The high-quality thin fi lms via a simple and cost-effective solution process are easily fabricated onto transparent and fl exible substrates at the relatively low temperature. Furthermore, the electrical properties of fi lms can be controlled by the amount of oxygen-functional groups attached to the GO sheets. [15][16][17][18] Reduced graphene oxide (rGO) can be produced from electrically insulating GO by removing the oxygen groups via thermal and chemical reductions. Therefore, GO thin fi lms can be used as a promising active layer in resistive switching memories [ 10,[19][20][21] as well as fl exible electrodes with highly conductive rGO sheets. [ 9,10,22,23 ] Many research groups have reported on GObased resistive switching memories that show superior memory properties when sandwiched with different metal electrode materials. [19][20][21][24][25][26][27] Recently, GO hybrid composites mixed with other materials such as a polymer, [ 28,29 ] nanoparticles, [ 30,31 ] or other 2D materials [ 32 ] have been widely studied to improve the performance of GO-based memory.The microscopic origin of the resistive switching phenomenon in GO-based memories has been generally explained by oxygen ion migration and the formation of a metal fi lament within GO fi lms. Fundamental studies of this microscopic origin have been limited to electrical I -V measurements at various temperatures [ 10,18,21,23 ] or chemical analysis methods. [ 31,33,34 ] These methods differ from those used to directly demonstrate the switching mechanisms of conventional transition-metal-oxide-based memories, by applying highly resolved techniques such as local conductivity atomic force microscopy (LC-AFM), [ 35,36 ] scanning probe microscopy (SPM), [ 37 ] and transmission electron microscopy (TEM). [38][39][40] The measurement limitations in GO-based memories are due to practical challenges such as sample preparation of 2D stacked GO nanosheets for advanced characterization. Although we previously reported on the nanoscale Al metallic fi lament induced at the top amorphous interface layer in Al/GO/Al resistive memory devices using high-resolution TEM (HRTEM) techniques, [ 19,20 ] revealing the existence of conducting path in a GO active layer remains a diffi cult challenge. The ability to visualize the conductive fi lament induced in Electrically insulating graphene oxide with various oxygen-functional groups is a novel material as an active layer in resistive switching memories via reduction process. Although many research groups have reported on graphene oxide-based resistive switching memories, revealing the origin of conducting path in a graphene oxide active layer remains a critical challenge. Here nanoscale conductive graphitic channels within graphene oxide fi lms are reported us...

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Section: Resultssupporting

confidence: 77%

Conductive Graphitic Channel in Graphene Oxide‐Based Memristive Devices

Kim

Jang

et al. 2016

Adv Funct Materials

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“…1350 cm −1 (D band) and 1585 cm −1 (G band). The I D /I G value decreases from 1.23 for NCNTs to 0.94 for NCNTs‐G, indicating enlarged graphitic domains in the latter, which is beneficial for electron transport . The undetectable Raman characteristic bands may be due to strong absorption of sulfur in the NCNTs, the small domain sizes of sulfur and the its inherent instability toward Raman laser ,.…”

Section: Resultsmentioning

confidence: 99%

Graphene Oxide Induced Growth of Nitrogen‐Doped Carbon Nanotubes as a 1D/2D Composite for High‐Performance Lithium‐Sulfur Batteries

et al. 2019

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A nitrogen-doped carbon nanotubes/graphene (NCNTs-G) composite as the sulfur host for a lithium-sulfur battery has been fabricated by in situ growth of NCNTs on graphene in a onestep nickel-catalyzed thermolysis. The graphene sheet can function as a robust support to anchor NCNTs so that the specific surface area of the composite can be increased and the charge-transfer resistance is reduced. These features, together with the high N-doping level, impart the NCNTs-G/S cathode a high utilization of sulfur, and the polysulfide shuttle effect can be effectively inhibited by both physical confinement and chemical adsorption. Therefore, the NCNTs-G/S cathode shows high reversible capacities of 1484 mA h g À 1 and 985 mA h g À 1 at the current rate of 0.1 C and 0.5 C, respectively. It also exhibits a good cycling stability; 82 % of its initial capacity is retained after 150 cycles at 0.5 C, and a very small capacity decay rate of 0.06 % per cycle resulted in 400 cycles at 1 C. Based on the above structural characteristics and battery performance results, the NCNTs-G/S is a promising cathode for a high-performance LiÀ S battery.

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“…These “newborn” RGO‐domains connect to form the CFs. Similar results of Raman mapping have also been reported in electrically reduced GO . That is, oxygen functional groups attached to graphene sheets can be detached by an electric field.…”

Section: Resultsmentioning

confidence: 94%

Photocatalytic Reduction of Graphene Oxide–TiO₂ Nanocomposites for Improving Resistive‐Switching Memory Behaviors

Zhao

Wang

et al. 2018

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Graphene oxide (GO)-based resistive-switching (RS) memories offer the promise of low-temperature solution-processability and high mechanical flexibility, making them ideally suited for future flexible electronic devices. The RS of GO can be recognized as electric-field-induced connection/disconnection of nanoscale reduced graphene oxide (RGO) conducting filaments (CFs). Instead of operating an electrical FORMING process, which generally results in high randomness of RGO CFs due to current overshoot, a TiO -assisted photocatalytic reduction method is used to generate RGO-domains locally through controlling the UV irradiation time and TiO concentration. The elimination of the FORMING process successfully suppresses the RGO overgrowth and improved RS memory characteristics are achieved in graphene oxide-TiO (Go-TiO ) nanocomposites, including reduced SET voltage, improved switching variability, and increased switching speed. Furthermore, the room-temperature process of this method is compatible with flexible plastic substrates and the memory cells exhibit excellent flexibility. Experimental results evidence that the combined advantages of reducing the oxygen-migration barrier and enhancing the local-electric-field with RGO-manipulation are responsible for the improved RS behaviors. These results offer valuable insight into the role of RGO-domains in GO memory devices, and also, this mild photoreduction method can be extended to the development of carbon-based flexible electronics.

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In Situ Raman Studies of Electrically Reduced Graphene Oxide and Its Field-Emission Properties

Cited by 46 publications

References 41 publications

Conductive Graphitic Channel in Graphene Oxide‐Based Memristive Devices

Conductive Graphitic Channel in Graphene Oxide‐Based Memristive Devices

Graphene Oxide Induced Growth of Nitrogen‐Doped Carbon Nanotubes as a 1D/2D Composite for High‐Performance Lithium‐Sulfur Batteries

Photocatalytic Reduction of Graphene Oxide–TiO₂ Nanocomposites for Improving Resistive‐Switching Memory Behaviors

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In Situ Raman Studies of Electrically Reduced Graphene Oxide and Its Field-Emission Properties

Cited by 46 publications

References 41 publications

Conductive Graphitic Channel in Graphene Oxide‐Based Memristive Devices

Conductive Graphitic Channel in Graphene Oxide‐Based Memristive Devices

Graphene Oxide Induced Growth of Nitrogen‐Doped Carbon Nanotubes as a 1D/2D Composite for High‐Performance Lithium‐Sulfur Batteries

Photocatalytic Reduction of Graphene Oxide–TiO2 Nanocomposites for Improving Resistive‐Switching Memory Behaviors

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Photocatalytic Reduction of Graphene Oxide–TiO₂ Nanocomposites for Improving Resistive‐Switching Memory Behaviors