Optoelectric Properties of Gate-Tunable MoS<sub>2</sub>/WSe<sub>2</sub>Heterojunction

Yi, So Young; Kim, Joo Hyoung; Min, Jung Ki; Park, Min Ji; Chang, Young Wook; Yoo, Keunje

doi:10.1109/tnano.2016.2547183

Cited by 17 publications

(18 citation statements)

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“…Graphene's optical properties can be tuned by changing its chemical potential, but it has small absorption in the visible part of the optical spectrum. Combining graphene with TMD layers allows one access to the best of both materials for applications like light harvesting and light emitting devices [46,47]. In general the total absorption of these two materials can be further enhanced by including also layers of QEs.…”

Section: Discussionmentioning

confidence: 99%

Near-field relaxation of a quantum emitter to two-dimensional semiconductors: Surface dissipation and exciton polaritons

et al. 2016

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The total spontaneous emission rate of a quantum emitter in the presence of an infinite MoS 2 monolayer is enhanced by several orders of magnitude, compared to its free-space value, due to the excitation of surface exciton polariton modes and lossy modes. The spectral and distance dependence of the spontaneous emission rate are analyzed and the lossy-surface-wave, surface exciton polariton mode and radiative contributions are identified. The transverse magnetic and transverse electric exciton polariton modes can be excited for different emission frequencies of the quantum emitter, and their contributions to the total spontaneous emission rate are different. To calculate these different decay rates, we use the non-Hermitian description of light-matter interactions, employing a Green's tensor formalism. The distance dependence follows different trends depending on the emission energy of quantum emitter. For the case of the lossy surface waves, the distance dependence follows a z −n , n = 2, 3, 4, trend. When transverse magnetic exciton polariton modes are excited, they dominate and characterize the distance dependence of the spontaneous emission rate of a quantum emitter in the presence of the MoS 2 layers. The interaction between a quantum emitter and a MoS 2 superlattice is investigated and we observe a splitting of the modes supported by the superlattice. Moreover, a blue shift of the peak values of the spontaneous emission rate of a quantum emitter is observed as the number of layers is increased. The field distribution profiles, created by a quantum emitter, are used to explain this behavior.

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Section: Discussionmentioning

confidence: 99%

Near-field relaxation of a quantum emitter to two-dimensional semiconductors: Surface dissipation and exciton polaritons

et al. 2016

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“…This discovery of graphene and TMD could open the door for next‐generation 2D‐material‐based optoelectronic applications. In this section, we review the development of 2D‐material‐based optoelectronic devices: i) photodetectors, ii) photovoltaic devices, and iii) LEDs …”

Section: Application Of 2d Materials To Optoelectronicsmentioning

confidence: 99%

“…Thus, new approaches have been explored to obtain high built‐in potentials inside photoactive 2D layers that can facilitate the dissociation of photocarriers and enhance the PCE value . Recently, many research groups have implemented 2D‐material‐based photovoltaic devices with a high built‐in potential by forming an asymmetric i) Schottky junction or ii) PN junction inside the photoactive 2D layer, as summarized in Table 9 . Shanmugam et al demonstrated a photovoltaic device based on an asymmetric Schottky junction with Au and indium tin oxide (ITO) contacts.…”

Section: Application Of 2d Materials To Optoelectronicsmentioning

confidence: 99%

“…The unique properties of graphene have also triggered extensive research in other 2D materials including TMDs, particularly for various electronic and optoelectronic device applications . 2D electronic devices have advanced from single junction to heterojunction devices and have recently been used in lateral/vertical field‐effect transistors (FETs), negative differential resistance (NDR) devices, and memory devices .…”

Section: Introductionmentioning

confidence: 99%

“…2D electronic devices have advanced from single junction to heterojunction devices and have recently been used in lateral/vertical field‐effect transistors (FETs), negative differential resistance (NDR) devices, and memory devices . Especially, type‐II heterojunctions have enabled efficient electron–hole separation during the conversion from light to current, and these have found use in high‐performance 2D optoelectronic devices such as photodetectors, photovoltaic devices, and light‐emitting diodes (LEDs) . The electronic and optoelectronic properties of semiconducting TMDs depend on the number of layers due to quantum confinement effects .…”

Section: Introductionmentioning

confidence: 99%

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Electronic and Optoelectronic Devices based on Two‐Dimensional Materials: From Fabrication to Application

Shim

Park

Kang

et al. 2017

Adv Elect Materials

145

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promising and important 2D material. Graphene-based electronic and optoelectronic device applications [11][12][13][14][15] have been widely researched to take advantage of its many outstanding properties, such as high carrier mobility (10 000 cm 2 V −1 s −1 at room temperature), [16] excellent optical transparency (97% for monolayer), [17] high Young's modulus (0.5-1 TPa), [18] and wide absorption spectrum (300-1400 nm). [19] The unique properties of graphene have also triggered extensive research in other 2D materials including TMDs, particularly for various electronic [4,[11][12][13] and optoelectronic device applications. [3,5,14,15,24,31, 2D electronic devices have advanced from single junction to heterojunction devices and have recently been used in lateral/vertical field-effect transistors (FETs), [4,[11][12][13][62][63][64]67,68] negative differential resistance (NDR) devices, [42][43][44][45][46][47][48][49][50]66] and memory devices. [51][52][53][54][55][56][57][58][59][60][61]65] Especially, type-II heterojunctions have enabled efficient electron-hole separation during the conversion from light to current, and these have found use in high-performance 2D optoelectronic devices such as photodetectors, [3,5,14,15,24,31,[69][70][71][72][73][74][75][76][77][78][79][80][81][82][83]102,103] photovoltaic devices, [84][85][86][87][88][89][90][91][92][93][94][95] and light-emitting diodes (LEDs). [87,88,[95][96][97][98][99][100][101] The electronic and optoelectronic properties of semiconducting TMDs depend on the number of layers due to quantum confinement effects. [104,105] For example, the transition from an indirect energy bandgap to a direct bandgap was observed for molybdenum-and tungstenbased TMDs as layer thickness decreases and approaches a monolayer. It has been reported that bulk molybdenum disulfide (MoS 2 ) and tungsten diselenide (WSe 2 ) have an indirect bandgap of 1.2 eV, whereas monolayer MoS 2 and WSe 2 have direct bandgaps of 1.88 eV and 1.65 eV, respectively, which lead to a high on/off-current ratio and high quantum efficiency. [106] Meanwhile, rhenium disulfide (ReS 2 ) exhibited a direct bandgap of 1.44 eV independent of its layer thickness, [107] and it is considered a promising candidate for future optoelectronic devices. [24,31,33,82,83] In this review, we first introduce important fabrication techniques of i) doping, ii) contact engineering, and iii) heterojunction formation for improving the performance of 2D-material-based devices in terms of fieldeffect mobility, on-current, responsivity, and temporal response (Section 2). We then discuss promising 2D-material-based electronic (Section 3) and optoelectronic (Section 4) devices,Since the rediscovery of graphene in 2004, this material has attracted an enormous amount of interest owing to its unique structural, mechanical, electronic, and optical properties. Beyond this, the unique properties of graphene have also triggered extensive research on other two-dimensional (2D) materials including transition metal dichalcogenides (TMDs), part...

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2D Tungsten Chalcogenides: Synthesis, Properties and Applications

Mohl

Rautio

Asres

et al. 2020

Adv Materials Inter

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Their fascinating properties are the result of the layered structure held together by weak van der Waals forces similarly to graphene, however, in TMDCs one layer is much more complex; consisting of a hexagonal plane of transition metals (typically metals of group IV-VII) sandwiched between two planes of chalcogens (S, Se, and Te) by strong covalent bonds (Figure 1). In 2004, the pioneering isolation of graphene sheets [1] gave a tremendous boost to the scientific community scrutinizing similar layered materials which can be separated relatively easily to single-layers or so-called monolayers. Based on their unique electronic transport properties and advantageous band structure these materials are suggested to have a great number of applications in transistors, [2][3][4] solar cells, [5][6][7] optoelectronic devices, [8,9] catalysts, [10] and sensors. [11] As might be anticipated their properties at atomic scale, greatly differ from their bulk counterpart. Recently, monolayers of MoS 2 and WS 2 have been found to exhibit direct semiconducting band gap in the visible spectrum rather than an indirect one that is well-known for their bulk phase. [12] In addition to material thickness, the band gap can be further fine-tuned, implying also beneficial changes in material properties, by doping TMDCs with different chalcogen atoms. As an example, when the thickness of MoS 2 is reduced from bulk to monolayer a significant increase in the band gap can be observed, from ≈1.2 to ≈1.8 eV, [12] accompanied with an indirectto-direct transition, and as expected, single layers also exhibit Layered transition metal chalcogenides possess properties that not only open up broad fundamental scientific enquiries but also indicate that a myriad of applications can be developed by using these materials. This is also true for tungsten-based chalcogenides which can provide an assortment of structural forms with different electronic flairs as well as chemical activity. Such emergence of tungsten based chalcogenides as advanced forms of materials lead several investigators to believe that a tremendous opportunity lies in understanding their fundamental properties, and by utilizing that knowledge the authors may create function specific materials through structural tailoring, defect engineering, chemical modifications as well as by combining them with other layered materials with complementary functionalities. Indeed several current scientific endeavors have indicated that an incredible potential for developing these materials for future applications development in key technology sectors such as energy, electronics, sensors, and catalysis are perhaps viable. This review article is an attempt to capture this essence by providing a summary of key scientific investigations related to various aspects of synthesis, characterization, modifications, and high value applications.Finally, some open questions and a discussion on imminent research needs and directions in developing tungsten based chalcogenide materials for future applications are present...

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Optoelectric Properties of Gate-Tunable MoS₂/WSe₂Heterojunction

Cited by 17 publications

References 26 publications

Near-field relaxation of a quantum emitter to two-dimensional semiconductors: Surface dissipation and exciton polaritons

Near-field relaxation of a quantum emitter to two-dimensional semiconductors: Surface dissipation and exciton polaritons

Electronic and Optoelectronic Devices based on Two‐Dimensional Materials: From Fabrication to Application

2D Tungsten Chalcogenides: Synthesis, Properties and Applications

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Optoelectric Properties of Gate-Tunable MoS2/WSe2Heterojunction

Cited by 17 publications

References 26 publications

Near-field relaxation of a quantum emitter to two-dimensional semiconductors: Surface dissipation and exciton polaritons

Near-field relaxation of a quantum emitter to two-dimensional semiconductors: Surface dissipation and exciton polaritons

Electronic and Optoelectronic Devices based on Two‐Dimensional Materials: From Fabrication to Application

2D Tungsten Chalcogenides: Synthesis, Properties and Applications

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Product

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Optoelectric Properties of Gate-Tunable MoS₂/WSe₂Heterojunction