Photocurrent generation at ABA/ABC lateral junction in tri-layer graphene photodetector

Kim, Minjung; Choi, Sang Joon; Yoon, Ho Ang; Choi, Sun Keun; Lee, Jae-Ung; Kim, Jungcheol; Lee, Sang Wook; Son, Young‐Woo; Cheong, Hyeonsik

doi:10.1016/j.carbon.2015.09.095

Cited by 11 publications

(8 citation statements)

References 45 publications

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“…This PTE current has been found to occur at the graphene–metal interface, graphene pn junction, monolayer–bilayer graphene junction, and ABA–ABC stacked graphene domain junction . In these devices, PTE is usually assumed to be dominant over PVE but the contrary has also been reported .…”

Section: Introductionmentioning

confidence: 99%

Competing Mechanisms for Photocurrent Induced at the Monolayer–Multilayer Graphene Junction

Zhang

Zheng

Wang

et al. 2018

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Graphene is characterized by demonstrated unique properties for potential novel applications in photodetection operated in the frequency range from ultraviolet to terahertz. To date, detailed work on identifying the origin of photoresponse in graphene is still ongoing. Here, scanning photocurrent microscopy to explore the nature of photocurrent generated at the monolayer-multilayer graphene junction is employed. It is found that the contributing photocurrent mechanism relies on the mismatch of the Dirac points between the monolayer and multilayer graphene. For overlapping Dirac points, only photothermoelectric effect (PTE) is observed at the junction. When they do not coincide, a different photocurrent due to photovoltaic effect (PVE) appears and becomes more pronounced with larger separation of the Dirac points. While only PTE is reported for a monolayer-bilayer graphene junction in the literature, this work confirms the coexistence of PTE and PVE, thereby extending the understanding of photocurrent in graphene-based heterojunctions.

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Section: Introductionmentioning

confidence: 99%

Competing Mechanisms for Photocurrent Induced at the Monolayer–Multilayer Graphene Junction

Zhang

Zheng

Wang

et al. 2018

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“…4,5 Several studies have revealed the influence of the stacking order on transport 6,7 and optical properties. [8][9][10][11][12] Hence, identifying the stacking sequences has become an important issue, and Raman spectroscopy has proven to be a reliable and easy characterization tool to identify stacking orders in few-layer graphene. [9][10][11]13 Since the Raman spectrum reflects the phonon dispersion and the electronic band structure, it is an ideal tool for fingerprinting the polytypes of graphene without complicated sample preparations.…”

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confidence: 99%

Raman Signatures of Polytypism in Molybdenum Disulfide

et al. 2016

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Since the stacking order sensitively affects various physical properties of layered materials, accurate determination of the stacking order is important for studying the basic properties of these materials as well as for device applications. Because 2H-molybdenum disulfide (MoS2) is most common in nature, most studies so far have focused on 2H-MoS2. However, we found that the 2H, 3R, and mixed stacking sequences exist in few-layer MoS2 exfoliated from natural molybdenite crystals. The crystal structures are confirmed by HR-TEM measurements. The Raman signatures of different polytypes are investigated by using 3 different excitation energies 2 which are non-resonant and resonant with A and C excitons, respectively. The low-frequency breathing and shear modes show distinct differences for each polytype whereas the highfrequency intra-layer modes show little difference. For resonant excitations at 1.96 and 2.81 eV, distinct features are observed which enable determination of the stacking order.3 Polytypism, a special type of polymorphism in layered materials, refers to different stacking sequences of monolayers with the same structure. 1-3 Since stacking sequence is one of the key attributes of layered materials, the effects of different stacking sequences on the electronic and other properties of 2-dimensional (2D) materials are of great interest. Although the crystal structure of each layer is identical, the properties of few-layer crystals are sensitively dependent on the stacking sequence due to different inter-layer interactions. For example, in the case of graphene, two stable stacking orders, ABA (Bernal) and ABC (rhombohedral) stacking orders, predominantly exist in nature. 4,5 Several studies have revealed the influence of the stacking order on transport 6,7 and optical properties. [8][9][10][11][12] Hence, identifying the stacking sequences has become an important issue, and Raman spectroscopy has proven to be a reliable and easy characterization tool to identify stacking orders in few-layer graphene. [9][10][11]13 Since the Raman spectrum reflects the phonon dispersion and the electronic band structure, it is an ideal tool for fingerprinting the polytypes of graphene without complicated sample preparations.In layered transition metal dichalcogenides (TMDs), polymorphism and polytypism are more important than in graphene because of more complex crystal structures. Among TMD materials, molybdenum disulfide (MoS2) is the most extensively studied. Thanks to a finite bandgap, electronic applications such as field effect transistors 14,15 or photodetectors 16,17 are explored.Single-layer MoS2 comprises a monolayer of Mo atoms sandwiched between two sulfur layers, forming a 'trilayer' (TL). 18,19 Each TL is connected via weak van der Waals interactions. Like other 2D materials, MoS2 has several polymorphs. For single-layer MoS2, there are two types of polymorphs: trigonal prism (1H-MoS2) and octahedral coordination (1T-MoS2). Since 1T-MoS2 is metastable, only the trigonal phase is found in natural bulk ...

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“…The NEP of the photodetector was measured to be 4 kW/cm 2 , thus an LDR of 44 dB has been obtained in the device which was 4 500 times larger than that of previously reported graphene photodetectors (LDR ≈ 7.5 dB) [154] and ~ 800 times larger than that of other functionalized graphene devices (LDR≈15 dB) [215]. ABA/ABC stacking domain junctions in tri-layer graphene is another FGPD design proposed for photocurrent generation [216]. Figures 20(a) and 20(b) present the stacking structures of 3LG with ABA and ABC stacking sequences [217].…”

Section: Full Graphene Photodetectorsmentioning

confidence: 77%

“…Stacking structures of 3LG[216] with (a) ABA and (b) ABC stacking sequences, (c) schematic of a graphene photodetector with a lateral junction between ABA-and ABC-stacked domains in 3LG (ABA/ABC photodetector), (d) comparison of 2D Raman peak line width (top) and photocurrent (bottom) images of 3 different ABA/ABC photodetectors, and (e) band alignment of the ABA/ABC junction in 3LG for VG = VCNP.…”

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confidence: 99%

An Effort Towards Full Graphene Photodetectors

et al. 2020

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Graphene as a truly 2-dimensional (2D) system is a promising candidate material for various optoelectronic applications. Implementing graphene as the main building material in ultra-broadband photodetectors has been the center of extensive research due to its unique absorption spectrum which covers most of the electro-magnetic spectra. However, one of the main challenges facing the wide application of pure graphene photodetectors has been the small optical absorption of monolayer graphene. Although novel designs were proposed to overcome this drawback, they often need complicated fabrication processes in order to integrate with the graphene photodetector. In this regard, fabrication of purely graphene photodetectors is a promising approach towards the manufacturing of simple, inexpensive, and high photosensitive devices. The fabrication of full graphene photodetectors (FGPDs) is mainly based on obtaining an optimal technique for the growth of high quality graphene, modification of electronic and optical properties of the graphene, appropriate techniques for transfer of graphene from the grown substrate to the desire position, and a proper design for photodetection. Therefore, the available states of the art techniques for each step of device fabrication, along with their pros and cons, are reviewed and the possible approaches for optimization of FGPDs have been proposed.

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Photocurrent generation at ABA/ABC lateral junction in tri-layer graphene photodetector

Cited by 11 publications

References 45 publications

Competing Mechanisms for Photocurrent Induced at the Monolayer–Multilayer Graphene Junction

Competing Mechanisms for Photocurrent Induced at the Monolayer–Multilayer Graphene Junction

Raman Signatures of Polytypism in Molybdenum Disulfide

An Effort Towards Full Graphene Photodetectors

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