Raman spectroscopy of graphene on AlGaN/GaN heterostructures

Dusari, S.; Goyal, Nitin; DeBiasio, M.; Kenda, A.

doi:10.1016/j.tsf.2015.11.041

Cited by 18 publications

(8 citation statements)

References 24 publications

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“…Interestingly, at longer growth time, the I2D/IG ratio was found to decrease to 1.2 for all the PH + CH used at higher Ar flow rates, in comparison to using shorter growth time where the Raman intensity ratio is in agreement with the reported value for bilayer graphene [27]. Thus, for growth conditions that are suitably carbon lean, the graphene growth Interestingly, at longer growth time, the I 2D /I G ratio was found to decrease to 1.2 for all the P H+CH used at higher Ar flow rates, in comparison to using shorter growth time where the Raman intensity ratio is in agreement with the reported value for bilayer graphene [27]. Thus, for growth conditions that are suitably carbon lean, the graphene growth self-limits to the bilayer.…”

Section: The Effect Of Growth Timesupporting

confidence: 83%

“…Increasing the growth time can also be seen to result in a line in the ternary plot which is a constant as the quality of graphene film remains insensitive to Ar flow rate at longer growth times (Figure 7). Interestingly, at longer growth time, the I2D/IG ratio was found to decrease to 1.2 for all the PH + CH used at higher Ar flow rates, in comparison to using shorter growth time where the Raman intensity ratio is in agreement with the reported value for bilayer graphene [27]. Thus, for growth conditions that are suitably carbon lean, the graphene growth self-limits to the bilayer.…”

Section: The Effect Of Growth Timesupporting

confidence: 78%

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Atmospheric Pressure Catalytic Vapor Deposition of Graphene on Liquid In and Cu-In Alloy Substrates

2021

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Liquid substrates are great candidates for the growth of high-quality graphene using chemical vapour deposition (CVD) due to their atomically flat and defect free surfaces. A detailed study of graphene growth using atmospheric pressure CVD (APCVD) on liquid indium (In) was conducted. It was found that the effect of the growth parameters on the quality of the graphene produced is highly dependent on the properties of the substrate used. A short residence time of 6.8 sec for the reactive gases led to a high graphene quality, indicating the good catalytic behaviour of In. The role of hydrogen partial pressure was found to be crucial, with monolayer and bilayer graphene films with a low defect density obtained at low PH2 (38.6 mbar), whilst more defective, thicker graphene films with a partial coverage being obtained at high PH2 (74.3 mbar). The graphene deposition was insensitive to growth time as the graphene growth on liquid In was found to self-limit to bilayer. For further investigation, five compositions of Cu-In alloys were made by arc-melting. Graphene was then grown using the optimum conditions for In and the quality of the graphene was found to degrade with increasing Cu wt.%. This work will aid the future optimisation of the growth conditions based upon the substrate’s properties.

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Section: The Effect Of Growth Timesupporting

confidence: 83%

Section: The Effect Of Growth Timesupporting

confidence: 78%

Atmospheric Pressure Catalytic Vapor Deposition of Graphene on Liquid In and Cu-In Alloy Substrates

2021

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“…Figure illustrates the Raman spectra of the flexible GaN/PDMS samples with and without the graphene layer. The peaks at 489 ± 1 (Si–O symmetry stretching), 709 ± 1 (C–Si–S symmetry stretching), 1411 ± 1 (C–H asymmetry stretching), 2906 ± 1 (C–H symmetry stretching), and 2966 ± 1 cm –1 (C–H asymmetry stretching) correspond to the PDMS substrate, while those at 568 ± 1 and 735 ± 1 cm –1 correspond to GaN . These peaks were observed in both of the samples.…”

Section: Results and Discussionmentioning

confidence: 87%

“…The peaks corresponding to GaN are fine and sharp, indicating its excellent crystalline behavior. Three prominent features can be observed in the graphene-transferred sample, namely, two peaks corresponding to D and 2D and one G peak . The D peak located at 1354 ± 1 cm –1 originates from the TO phonon mode near the K points in the Brillouin zone.…”

Section: Results and Discussionmentioning

confidence: 97%

Strain-Controlled Flexible Graphene/GaN/PDMS Sensors Based on the Piezotronic Effect

Puneetha

Mallem

Lee

et al. 2020

ACS Appl. Mater. Interfaces

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Using simple graphene transfer and the laser lift-off process for a non-centrosymmetric GaN layer on a flexible polydimethylsiloxane (PDMS) substrate, the piezotronic effect by strain-induced current−voltage measurements at the two end points is studied. By inducing compressive strain on the flexible graphene/GaN/PDMS sensor, the Schottky barrier between the graphene and GaN/PDMS heterojunction can be electromechanically modulated by the piezotronic effect. It is observed that the flexible graphene/GaN/PDMS sensor is sensitive to various applied compressive and tensile strains in the positive/ negative bias scans. The sensor is extremely sensitive to a compressive strain of −0.1% with a gauge factor of 13.48, which is 3.7 times higher than that of a standard metal strain gauge. Furthermore, the sharp response of the flexible graphene/GaN/ PDMS sensor under the −0.1% compressive strain is also investigated. The results of this study herald the development of commercially viable large-scale flexible/wearable strain sensors based on the strain-controlled piezotronic effect in future investigations.

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“…The silicon substrate peak at 520cm -1 is so strong that makes the E 2 (high) weakened. The A 1 (LO) mode of three samples in different temperatures are observed in the region 584~612cm -1 which refers that the A 1 (LO) mode of InN located in 570cm -1 and 733.07cm -1 for GaN [7]. The peak positions move towards lower wavenumbers while the In compositions x increases, the main reason for this shift is structural defects in films.…”

Section: Resultsmentioning

confidence: 75%

Structural and Morphological Characteristics of In_xga_1-xN Films Grown on SI (111) by Reactive Magnetron Sputtering

Wang

et al. 2016

MATEC Web Conf.

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Raman spectroscopy of graphene on AlGaN/GaN heterostructures

Cited by 18 publications

References 24 publications

Atmospheric Pressure Catalytic Vapor Deposition of Graphene on Liquid In and Cu-In Alloy Substrates

Atmospheric Pressure Catalytic Vapor Deposition of Graphene on Liquid In and Cu-In Alloy Substrates

Strain-Controlled Flexible Graphene/GaN/PDMS Sensors Based on the Piezotronic Effect

Structural and Morphological Characteristics of In_xga_1-xN Films Grown on SI (111) by Reactive Magnetron Sputtering

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Raman spectroscopy of graphene on AlGaN/GaN heterostructures

Cited by 18 publications

References 24 publications

Atmospheric Pressure Catalytic Vapor Deposition of Graphene on Liquid In and Cu-In Alloy Substrates

Atmospheric Pressure Catalytic Vapor Deposition of Graphene on Liquid In and Cu-In Alloy Substrates

Strain-Controlled Flexible Graphene/GaN/PDMS Sensors Based on the Piezotronic Effect

Structural and Morphological Characteristics of Inxga1-xN Films Grown on SI (111) by Reactive Magnetron Sputtering

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Resources

About

Structural and Morphological Characteristics of In_xga_1-xN Films Grown on SI (111) by Reactive Magnetron Sputtering