A MoSe<sub>2</sub>/WSe<sub>2</sub> Heterojunction‐Based Photodetector at Telecommunication Wavelengths

Xue, Hui; Wang, Yadong; Dai, Yunyun; Kim, Wonjae; Jussila, Henri; Qi, Mei; Susoma, Jannatul; Ren, Zhaoyu; Dai, Qing; Zhao, Jianlin; Halonen, K.; Lipsanen, Harri; Wang, Xiaomu; Sun, Zhipei

doi:10.1002/adfm.201804388

Cited by 109 publications

(81 citation statements)

References 48 publications

(31 reference statements)

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“…This observation rules out the contribution of sub-bandgap traps (if any) in the photocurrent generation across the interlayer bandgap. 58,59 Absence of photoresponse in an individual WSe2 FET (inset in Figure 6e) when subjected to IR radiation under the same set-up reinforces the sub-bandgap (type-II) interlayer photogeneration across the heterointerface. A schematic depicting the energy range involved in the optical measurements in comparison to the DFT interlayer bandgap values and the bandgaps of individual WSe2 and ReS2 layers is shown in Figure 6f for better visualization.…”

Section: Photovoltaic Effect and Ir Photoresponsementioning

confidence: 70%

Near-Direct Bandgap WSe₂/ReS₂ Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics

et al. 2020

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PN heterojunctions comprising layered van der Waals (vdW) semiconductors have been used to demonstrate current rectifiers, photodetectors, and photovoltaic devices. However, a direct or neardirect bandgap at the heterointerface that can significantly enhance optical generation, for high light absorbing few/multi-layer vdW materials, has not yet been shown. In this work, for the first time, few-layer group-6 transition metal dichalcogenide (TMD) WSe2 is shown to form a sizeable (0.7 eV) near-direct bandgap with type-II band alignment at its interface with the group-7 TMD ReS2 through density functional theory calculations. Further, the type-II alignment and photogeneration across the interlayer bandgap have been experimentally confirmed through micro-photoluminescence and IR 2 photodetection measurements, respectively. High optical absorption in few-layer flakes, large conduction and valence band offsets for efficient electron-hole separation and stacking of light facing, direct bandgap ReS2 on top of gate tunable WSe2 are shown to result in excellent and tunable photodetection as well as photovoltaic performance through flake thickness dependent optoelectronic measurements. Few-layer flakes demonstrate ultrafast response time (5 µs) at high responsivity (3 A/W) and large photocurrent generation and responsivity enhancement at the heterostructure overlap region (10-100×) for 532 nm laser illumination. Large open circuit voltage of 0.64 V and short circuit current of 2.6 µA enables high output electrical power. Finally, long term air-stability and a facile single contact metal fabrication process makes the multi-functional few-layer WSe2/ReS2 heterostructure diode technologically promising for next-generation optoelectronic applications.The semiconducting group-6 TMD WSe2, generally found in trigonal prismatic phase, 17 is an indirect bandgap material in its bulk form. 18,19 However, group-7 TMD e.g. 1T phase of ReS2 is distorted octahedral in structure 17,20 and exhibits direct (or, near-direct) bandgap at (or, close to) the Γ point of the Brillouin zone (BZ). Interestingly, unlike the group-6 TMDs, ReS2 exhibits a unique property owing to its distorted structure and weak interlayer coupling-the direct or near-direct nature of its bandgap remains unchanged from monolayer to bulk. [20][21][22] Closer examination of the bandstructure of group-7 TMDs reveals that the conduction band minimum of ReS2 remains at the Γ point, irrespective of the number of layers. 20,23 But for group-6 TMDs (such as WSe2) the valence band maximum relocates from K to Γ point of the BZ with increasing number of layers. 18,24 It is important to note that the valence band maximum at the Γ point differs in energy only slightly from that at the K point. 18 This gives rise to an increased probability of direct as well as indirect transitions from the Γ and the K valence maxima of WSe2 to the Γ conduction minimum of ReS2 respectively, for a predicted type-II band alignment. The possibility of a direct bandgap transition is not observed in a heter...

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Section: Photovoltaic Effect and Ir Photoresponsementioning

confidence: 70%

Near-Direct Bandgap WSe₂/ReS₂ Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics

et al. 2020

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“…2D materials have good application prospects in the field of photodetectors due to their excellent optical and electronic properties. At present, many photodetectors based on 2D materials have been reported and have exhibited excellent photodetection performance . Xia et al demonstrated a single‐layer and few‐layer graphene‐based transistor photodetector with ultrafast photoresponse characteristics, wide optical absorption wavelength, and good internal quantum efficiency.…”

Section: The Emergence Of 2d Materialsmentioning

confidence: 99%

“…At present, many photodetectors based on 2D materials have been reported and have exhibited excellent photodetection performance. [151][152][153][154][155][156] Xia et al [157] demonstrated a single-layer and few-layer graphene-based transistor photodetector with ultrafast photoresponse characteristics, wide optical absorption wavelength, and good internal quantum efficiency. Although graphene photodetectors exhibit excellent photodetector behavior, [158][159][160][161] it is difficult to open zero bandgaps, and low light absorption [162][163][164] (only 2.3% light absorptivity) limits its application in photodetection devices.…”

Section: Application Of 2d Materials On Photodetectorsmentioning

confidence: 99%

Self‐Powered Photodetectors Based on 2D Materials

Qiao

Huang

Ren

et al. 2019

Advanced Optical Materials

291

225

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Self‐powered photodetectors are considered as a new type of photodetectors enabling self‐powered photodetection without external power. The excellent photoresponsivity, fast photoresponse rate, low dark current, and large light on/off ratio of these photodetectors have attracted wide interest among scholars. 2D materials are widely used in self‐powered photodetectors due to their excellent optical and electrical properties, unique 2D structures, and their capabilities to exhibit excellent photodetection performance. According to the self‐driving mechanism of 2D material‐based self‐powered photodetectors, they are divided into three categories: p–n junction photodetectors, Schottky junction photodetectors, and photoelectrochemical photodetectors. From these three perspectives, the research progress of 2D material‐based self‐powered photodetectors is summarized in detail here. Research reports indicate that 2D material‐based self‐powered photodetectors have excellent self‐powered photoresponse behavior, good light on/off characteristics, and wideband spectral response ranges. The excellent photoresponse performance of 2D material‐based self‐powered photodetectors facilitates their potential applications in the field of optoelectronic devices. In particular, self‐powered photodetectors have great potential as novel emerging self‐driven optoelectronic devices. Finally, directions for the further development of 2D material‐based self‐powered photodetectors are anticipated.

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“…In addition to mechanically exfoliated nanosheets, materials prepared with chemical vapor deposition (CVD) can also be manually stacked . Many heterostructures have been produced, such as MoS 2 /WS 2 , graphene/MoS 2 , MoSe 2 /graphene, and MoS 2 /WSe 2 , for flexible IR photodetectors and image sensor arrays.…”

Section: Production Of 2dhsmentioning

confidence: 99%

Two‐dimensional heterostructure promoted infrared photodetection devices

Rao

Wang

et al. 2019

InfoMat

115

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It is a rapidly developed subject in expanding the fundamental properties and application of two‐dimensional (2D) materials. The weak van der Waals interaction in 2D materials inspired researchers to explore 2D heterostructures (2DHs) based broadband photodetectors in the far‐infrared (IR) and middle‐IR regions with high response and high detectivity. This review focuses on the strategy and motivation of designing 2DHs based high‐performance IR photodetectors, which provides a wide view of this field and new expectation for advanced photodetectors. First, the photocarriers' generation mechanism and frequently employed device structures are presented. Then, the 2DHs are divided into semimetal/semiconductor 2DHs, semiconductor/semiconductor 2DHs, and multidimensional semi‐2DHs; the advantages, motivation, mechanism, recent progress, and outlook are discussed. Finally, the challenges for next‐generation photodetectors are described for this rapidly developing field.

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A MoSe₂/WSe₂ Heterojunction‐Based Photodetector at Telecommunication Wavelengths

Cited by 109 publications

References 48 publications

Near-Direct Bandgap WSe₂/ReS₂ Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics

Near-Direct Bandgap WSe₂/ReS₂ Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics

Self‐Powered Photodetectors Based on 2D Materials

Two‐dimensional heterostructure promoted infrared photodetection devices

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A MoSe2/WSe2 Heterojunction‐Based Photodetector at Telecommunication Wavelengths

Cited by 109 publications

References 48 publications

Near-Direct Bandgap WSe2/ReS2 Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics

Near-Direct Bandgap WSe2/ReS2 Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics

Self‐Powered Photodetectors Based on 2D Materials

Two‐dimensional heterostructure promoted infrared photodetection devices

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A MoSe₂/WSe₂ Heterojunction‐Based Photodetector at Telecommunication Wavelengths

Near-Direct Bandgap WSe₂/ReS₂ Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics

Near-Direct Bandgap WSe₂/ReS₂ Type-II pn Heterojunction for Enhanced Ultrafast Photodetection and High-Performance Photovoltaics