Single-step deposition of high-mobility graphene at reduced temperatures

Boyd, David A.; Lin, Wei‐Hsiang; Hsu, Chang-Hong; Teague, M. L.; Chen, C.-C.; Lo, Yuan-Yen; Chan, Weimin; Su, Wei-Bin; Cheng, Tsung-Chin; Chang, Cheng-Shang; Wu, Chih-I; Yeh, N.-C.

doi:10.1038/ncomms7620

Cited by 184 publications

(125 citation statements)

References 30 publications

(78 reference statements)

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“…This low photocatalytic performance may be attributed to the fast charge recombination [44,45]. Graphene thin film also shows a poor involvement in chemical conversion, as observed by others also, e.g., [46], here about 5% after 60 min. In the case of graphene-TiO 2 thin films, it is observed that under illumination, the spin-SVPT and SVASC samples linearly degrade the contaminant, and after 60 min about 77% and 84% of MB in water is removed, respectively.…”

Section: Resultsmentioning

confidence: 72%

Photocatalytic Graphene-TiO2 Thin Films Fabricated by Low-Temperature Ultrasonic Vibration-Assisted Spin and Spray Coating in a Sol-Gel Process

2017

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Abstract:In this work, we communicate a facile and low temperature synthesis process for the fabrication of graphene-TiO 2 photocatalytic composite thin films. A sol-gel chemical route is used to synthesize TiO 2 from the precursor solutions and spin and spray coating are used to deposit the films. Excitation of the wet films during the casting process by ultrasonic vibration favorably influences both the sol-gel route and the deposition process, through the following mechanisms. The ultrasound energy imparted to the wet film breaks down the physical bonds of the gel phase. As a result, only a low-temperature post annealing process is required to eliminate the residues to complete the conversion of precursors to TiO 2 . In addition, ultrasonic vibration creates a nanoscale agitating motion or microstreaming in the liquid film that facilitates mixing of TiO 2 and graphene nanosheets. The films made based on the above-mentioned ultrasonic vibration-assisted method and annealed at 150 • C contain both rutile and anatase phases of TiO 2 , which is the most favorable configuration for photocatalytic applications. The photoinduced and photocatalytic experiments demonstrate effective photocurrent generation and elimination of pollutants by graphene-TiO 2 composite thin films fabricated via scalable spray coating and mild temperature processing, the results of which are comparable with those made using lab-scale and energy-intensive processes.

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Section: Resultsmentioning

confidence: 72%

Photocatalytic Graphene-TiO2 Thin Films Fabricated by Low-Temperature Ultrasonic Vibration-Assisted Spin and Spray Coating in a Sol-Gel Process

2017

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“…Low Temperature Plasma CVD Grown Graphene by Microwave Surface-Wave Plasma CVD Using Camphor Precursor 38 substrates as suggest by Boyd et al [11]. Present results show that camphor precursor could be the best choice for graphene growth at low temperature as oxygen present in the camphor molecule is seen to be beneficial for both controlling the thickness and passivating Cu substrate during growth.…”

Section: -Probe Sheet Resistance Transmissionmentioning

confidence: 51%

“…Moreover, the film deposited using camphor shows superior quality than that of the film deposited by using methane. Other defect related peaks such as D` peak around 1,625 cm -1 (shoulder peak of G peak) [5,11] and the peak around 2,944 cm -1 is reduced preciously while placing cover above the substrate during growth. These two defect-related peaks are almost invisible in the case of the film deposited by using camphor precursor, which indicates the merit of carbon source (a) with direct exposure of substrate to plasma; (b) avoiding direct exposure of substrate to plasma.…”

Section: Resultsmentioning

confidence: 99%

Low Temperature Plasma CVD Grown Graphene by Microwave Surface-Wave Plasma CVD Using Camphor Precursor

Uchida¹,

Aryal²,

Adhikari³

2016

JPSA

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Hydrocarbon precursor such as methane has been widely used to grow graphene films and the methods of growing quality graphene films are dominated by thermal CVD (chemical vapor deposition) system. Graphene films grown by plasma process are generally highly defective which in turns degrade the quality of the films. Here, using a green precursor, camphor we demonstrate a simple and economical method to get high-quality graphene film on copper substrate by micro wave surface-wave plasma CVD at relatively low temperature 550℃. Graphene film grown using camphor shows superior quality than that of the film grown using methane. Results revealed that camphor precursor is a good alternative to hydrocarbon precursors for graphene research.

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“…For the purposes of this review, it is interesting to focus on a few unique features of graphene, such as its high mobility and wide carrier concentration tuning range. Room temperature mobilities, which can be as high as ~10 5 cm 2 V −1 s −1 [21,22], and carrier concentration modulations, up to ~10 14 cm −2 [23], make graphene attractive because they provide a wider spanning range useful for active modulation. The optical conductivity in graphene at THz frequency is well described by the Kubo formula [24] considering only the intraband contribution.…”

Section: Basic Theoretical Principlementioning

confidence: 99%

All-integrated terahertz modulators

et al. 2017

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Terahertz (0.1-10 THz corresponding to vacuum wavelengths between 30 μm and 3 mm) research has experienced impressive progress in the last few decades. The importance of this frequency range stems from unique applications in several fields, including spectroscopy, communications, and imaging. THz emitters have experienced great development recently with the advent of the quantum cascade laser, the improvement in the frequency range covered by electronic-based sources, and the increased performance and versatility of time domain spectroscopic systems based on full-spectrum lasers. However, the lack of suitable active optoelectronic devices has hindered the ability of THz technologies to fulfill their potential. The high demand for fast, efficient integrated optical components, such as amplitude, frequency, and polarization modulators, is driving one of the most challenging research areas in photonics. This is partly due to the inherent difficulties in using conventional integrated modulation techniques. This article aims to provide an overview of the different approaches and techniques recently employed in order to overcome this bottleneck.

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Single-step deposition of high-mobility graphene at reduced temperatures

Cited by 184 publications

References 30 publications

Photocatalytic Graphene-TiO2 Thin Films Fabricated by Low-Temperature Ultrasonic Vibration-Assisted Spin and Spray Coating in a Sol-Gel Process

Photocatalytic Graphene-TiO2 Thin Films Fabricated by Low-Temperature Ultrasonic Vibration-Assisted Spin and Spray Coating in a Sol-Gel Process

Low Temperature Plasma CVD Grown Graphene by Microwave Surface-Wave Plasma CVD Using Camphor Precursor

All-integrated terahertz modulators

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