Layer-Dependent Optical Conductivity in Atomic Thin WS<sub>2</sub> by Reflection Contrast Spectroscopy

Nayak, Pramoda K.; Yeh, Chao‐Hui; Chen, Yu‐Chen; Chiu, Po‐Wen

doi:10.1021/am5039483

Cited by 34 publications

(26 citation statements)

References 46 publications

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“…As previously reported [36,[39][40] , Al: WS 2 films are indirect band gap semiconductor. As previously reported [36,[39][40] , Al: WS 2 films are indirect band gap semiconductor.…”

Section: Fig 3 (A)-(c) Show the Optical Transmittance (T) (Inset: Resupporting

confidence: 69%

Optical and electrical properties of Al:WS₂ films prepared by atomic layer deposition and vulcanization

Feng

et al. 2016

RSC Adv.

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Composition, structure, optical and electrical properties of Al: WS 2 (un-doped and Al-doped WS 2 ) films prepared by atomic layer deposition (ALD) and CS 2 vulcanization processing have been studied. Results show that Al: WS 2 films grow with a preferential c⊥-orientation. The core-level binding energies (BEs) of W 4f, S 2p, O 1s and Al 2s decrease with increasing Al doping content, indicating that Al-doped WS 2 films are p-type conductivity. Optical properties analysis shows that Absorption coefficient (∼10 7 m -1 ) is comparable to that of WS 2 single crystals, and Al doping contents can tune the optical band gaps of the films. Hall measurement shows that p-type conductive Al-doped WS 2 films can be obtained by Al doping. Hall mobility values of the un-doped WS 2 and 2.40% Al-doped WS 2 films are 1.63×10 1 and 9.71 cm 2 V -1 s -1 , respectively. Comparing with un-doped WS 2 films, the comparable Hall mobility of Al-doped WS 2 films can be achieved by appropriate Al doping contents.

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“…As previously reported [36,[39][40] , Al: WS 2 films are indirect band gap semiconductor. As previously reported [36,[39][40] , Al: WS 2 films are indirect band gap semiconductor.…”

Section: Fig 3 (A)-(c) Show the Optical Transmittance (T) (Inset: Resupporting

confidence: 69%

Optical and electrical properties of Al:WS₂ films prepared by atomic layer deposition and vulcanization

Feng

et al. 2016

RSC Adv.

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“…Due to the large index mismatch, a large fraction (50-60%) of the incident light is reflected back from the surface of bulk crystals 35,36 (See supporting information figure S1). Likewise, the absorption in few layer-bulk TMDCs on the conventionally used Si/SiO2 substrates is also limited to a maximum between 50-60% 37,38 The above observations are not unique to WSe2 and can be further generalized to other TMDCs Although the absorption peaks in our structure are dependent on path length, they are highly insensitive to the angle of incidence as a can be seen for the case of 13 nm WSe2 on Ag ( Figure 3a). The peak absorption stays over 80% even at a 60˚ incident angle (Figure 3 b) suggesting relatively low sensitivity to the angle of incident light.…”

Section: F)mentioning

confidence: 53%

Near-Unity Absorption in van der Waals Semiconductors for Ultrathin Optoelectronics

et al. 2016

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We demonstrate near-unity, broadband absorbing optoelectronic devices using sub-15 nm thick transition metal dichalcogenides (TMDCs) of molybdenum and tungsten as van der Waals semiconductor active layers. Specifically, we report that near-unity light absorption is possible in extremely thin (<15 nm) van der Waals semiconductor structures by coupling to strongly damped optical modes of semiconductor/metal heterostructures. We further fabricate Schottky junction devices using these highly absorbing heterostructures and characterize their optoelectronic performance. Our work addresses one of the key criteria to enable TMDCs as potential candidates to achieve high optoelectronic efficiency.

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“…2D TMDs exhibit strong light‐matter interaction, good optical conductivity, and high charge mobility, making them efficient HTLs for HPSCs . Kim et al applied 2D TMDs including MoS 2 and WS 2 as HTLs for MAPbI 3– x Cl x ‐based planar HPSCs (Figure d) .…”

Section: D Materials For Halide Perovskite Solar Cellsmentioning

confidence: 99%

Two‐Dimensional Materials for Halide Perovskite‐Based Optoelectronic Devices

2017

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Halide perovskites have high light absorption coefficients, long charge carrier diffusion lengths, intense photoluminescence, and slow rates of non-radiative charge recombination. Thus, they are attractive photoactive materials for developing high-performance optoelectronic devices. These devices are also cheap and easy to be fabricated. To realize the optimal performances of halide perovskite-based optoelectronic devices (HPODs), perovskite photoactive layers should work effectively with other functional materials such as electrodes, interfacial layers and encapsulating films. Conventional two-dimensional (2D) materials are promising candidates for this purpose because of their unique structures and/or interesting optoelectronic properties. Here, we comprehensively summarize the recent advancements in the applications of conventional 2D materials for halide perovskite-based photodetectors, solar cells and light-emitting diodes. The examples of these 2D materials are graphene and its derivatives, mono- and few-layer transition metal dichalcogenides (TMDs), graphdiyne and metal nanosheets, etc. The research related to 2D nanostructured perovskites and 2D Ruddlesden-Popper perovskites as efficient and stable photoactive layers is also outlined. The syntheses, functions and working mechanisms of relevant 2D materials are introduced, and the challenges to achieving practical applications of HPODs using 2D materials are also discussed.

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Layer-Dependent Optical Conductivity in Atomic Thin WS₂ by Reflection Contrast Spectroscopy

Cited by 34 publications

References 46 publications

Optical and electrical properties of Al:WS₂ films prepared by atomic layer deposition and vulcanization

Optical and electrical properties of Al:WS₂ films prepared by atomic layer deposition and vulcanization

Near-Unity Absorption in van der Waals Semiconductors for Ultrathin Optoelectronics

Two‐Dimensional Materials for Halide Perovskite‐Based Optoelectronic Devices

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Layer-Dependent Optical Conductivity in Atomic Thin WS2 by Reflection Contrast Spectroscopy

Cited by 34 publications

References 46 publications

Optical and electrical properties of Al:WS2 films prepared by atomic layer deposition and vulcanization

Optical and electrical properties of Al:WS2 films prepared by atomic layer deposition and vulcanization

Near-Unity Absorption in van der Waals Semiconductors for Ultrathin Optoelectronics

Two‐Dimensional Materials for Halide Perovskite‐Based Optoelectronic Devices

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Product

Resources

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Layer-Dependent Optical Conductivity in Atomic Thin WS₂ by Reflection Contrast Spectroscopy

Optical and electrical properties of Al:WS₂ films prepared by atomic layer deposition and vulcanization

Optical and electrical properties of Al:WS₂ films prepared by atomic layer deposition and vulcanization