Growth and application of WSe2 single crystal synthesized by DVT in thin film hetero-junction photodetector

Dixit, V. K.; Nair, Salil; Joy, Jolly; Vyas, C. U.; Patel, Alkesh B.; Chauhan, Payal; Sumesh, C.K.; Som, Narayan N.; Jha, Prafulla K.; Solanki, G. K.; Patel, K. C.; Pathak, V. M.

doi:10.1140/epjb/e2019-90736-3

Cited by 20 publications

(13 citation statements)

References 57 publications

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“…The dominance of (00l) planes indicates the hexagonal crystal structure formation and the highly c-axis-oriented stacking of layers. 21,23 The observed peaks match well with the already reported data of WSe 2 , 21,24 confirming the proper replacement of W (atomic radius 1.93 Å) by Co (atomic radius 1.52 Å) in the host sample. However, two low-intensity peaks at (101) and (012) indexed to cubic structure with Pa-3 space group were identified.…”

Section: Characterization Techniquessupporting

confidence: 87%

“…The detectivity of Co 0.25 W 0.75 Se 2 , even at zero bias, seems to be better than that of pure WSe 2. 21 At the same time, its response time is better than that of PLD grown WSe 2, 16 confirming the improvement in the photoresponse parameters on incorporating Co to WSe 2 . The distortion in the shape of the pulsed photoresponse might be because the analysis was performed in an open environment where the probability of adsorption of gaseous impurities on the crystal surface needs to be taken into account.…”

Section: Resultsmentioning

confidence: 82%

“…In Figure 3A,B, the hexagonal‐shaped spirals indicate the screw dislocations that occur during the growth mechanism of the crystals. Such spirals of different shapes are quite common in crystals grown by the DVT technique showing the growth from the vapour phase 21,22 . The shapes of the spirals are defined based on the rate of movement of dislocations in different directions.…”

Section: Resultsmentioning

confidence: 99%

“…Such spirals of different shapes are quite common in crystals grown by the DVT technique showing the growth from the vapour phase. 21,22 The shapes of the spirals are defined based on the rate of movement of dislocations in different directions. Concurrently, the layered structure of the crystals can be seen at the edges of the crystal, which is due to the termination of the layers.…”

Section: Characterization Techniquesmentioning

confidence: 99%

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Enhancement in the transient visible light anisotropic photoresponse of cobalt‐incorporated tungsten diselenide ternary alloy

Joy

Nair

Dixit

et al. 2021

Intl J of Energy Research

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Anisotropy in the optical and electrical properties of many transition metal dichalcogenides provides a great variety of possibilities for device applications.The present work attempts to exploit the anisotropy in photoresponse of pure and Co-incorporated WSe 2 crystals. Energy-dispersive analysis of X-rays affirmed the elemental composition of the crystals grown by the direct vapour transport technique. The surface morphology of the crystals was studied by optical microscopy and scanning electron microscopy, both of which confirmed the layered structure of the same. Layers of the samples and the lattice fringes were concluded under high-resolution transmission electron microscopy. The crystalline nature and hexagonal phase of the crystals were confirmed from X-ray diffraction, further highlighted in the results observed from the selected area electron diffraction pattern. Anisotropic charge conduction properties under illumination due to the layered structure of the sample were analysed. The anisotropy in the photoresponse was confirmed from the current-voltage (I-V) characteristics, which were further explored from its time-dependent photoresponse. The crystals proved to be self-powered photodetectors with higher values of photocurrent (μA), photoresponsivity (μAW À1 ) and photodetectivity (~10 7 -10 8 Jones) recorded for contacts taken parallel to the crystallographic c-axis of the crystals. The effect of Co in improving the photoconductivity of WSe 2 has been analysed based on the photoresponse recorded for pure and Co-incorporated WSe 2 . The present work also illustrates the effect of intensities of illumination and wavelengths of incident radiations in the photocurrent. Photocurrent in μA range observed in the absence of biasing voltage makes the crystals suitable candidates for self-powered photodetection applications.

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Section: Characterization Techniquessupporting

confidence: 87%

Section: Resultsmentioning

confidence: 82%

Section: Resultsmentioning

confidence: 99%

Section: Characterization Techniquesmentioning

confidence: 99%

See 2 more Smart Citations

Enhancement in the transient visible light anisotropic photoresponse of cobalt‐incorporated tungsten diselenide ternary alloy

Joy

Nair

Dixit

et al. 2021

Intl J of Energy Research

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“…Strong reflection peaks were observed at (002), (006), and (008), while other peaks were well indexed at (004) and (0010) corresponding to the hexagonal lattice structure of WSe 2 , which are in accordance with already reported values. 25 On a closer view of the XRD patterns, a shift in the peaks slightly towards the higher diffraction angles for Ni (4%) WSe 2 was observed compared to Pure WSe 2 . The shifting of this sort is a direct consequence of the differences in the atomic radius of the parent atoms, that is, W (0.141 nm) and Se (0.120 nm) with that of Ni (0.124 nm), which was also stated by Bragg's law, that smaller atomic radii in comparison to the parent atoms could develop a compressive strain in the lattice which ultimately shifts the peak to a higher diffraction angle.…”

Section: Resultsmentioning

confidence: 83%

Dye‐sensitized solar cells based on nickel‐doped tungsten diselenide counter electrodes

2021

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Dye-sensitized solar cells (DSSCs) are gaining considerable interest as substitutes to solar cells based on semiconductor thin-films owing to their costeffective and effortless fabrication methods. Efforts are being made to replace counter electrodes (CE) in DSSCs, which are conventionally based on noble metal platinum (Pt). Among the new materials as CE, two-dimensional (2D) transition metal dichalcogenide is one of the most explored to develop Pt-free DSSCs. We report here the preparation of TiO 2 -based DSSCs using beetroot (Beta vulgaris) extracts as sensitizers with carbon-, pristine-, and Ni (4%)-doped WSe 2 as the CEs. The Ni (4%) WSe 2 CE exhibited a high-power conversion efficiency (PCE) of 5.66% under the illumination of 100 mW cm À2 .The electrical characteristics, including I-V, C-V, and electrochemical impedance spectroscopy, corroborate the better efficiency of Ni (4%) WSe 2 CE. The cost-effectiveness and efficiencies obtained for Pure and Ni (4%) WSe 2 make them a worthy candidate as CE for DSSCs.

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Tunable Linearity of High‐Performance Vertical Dual‐Gate vdW Phototransistors

Luo

et al. 2021

Advanced Materials

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Layered 2D semiconductors have been widely exploited in photodetectors due to their excellent electronic and optoelectronic properties. To improve their performance, photogating, photoconductive, photovoltaic, photothermoelectric, and other effects have been used in phototransistors and photodiodes made with 2D semiconductors or hybrid structures. However, it is difficult to achieve the desired high responsivity and linear photoresponse simultaneously in a monopolar conduction channel or a p–n junction. Here, dual‐channel conduction with ambipolar multilayer WSe2 is presented by employing the device concept of dual‐gate phototransistor, where p‐type and n‐type channels are produced in the same semiconductor using opposite dual‐gating. It is possible to tune the photoconductive gain using a vertical electric field, so that the gain is constant with respect to the light intensity—a linear photoresponse, with a high responsivity of ≈2.5 × 104 A W−1. Additionally, the 1/f noise of the device is kept at a low level under the opposite dual‐gating due to the reduction of current and carrier fluctuation, resulting in a high detectivity of ≈2 × 1013 Jones in the linear photoresponse regime. The linear photoresponse and high performance of the dual‐gate WSe2 phototransistor offer the possibility of achieving high‐resolution and quantitative light detection with layered 2D semiconductors.

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Growth and application of WSe2 single crystal synthesized by DVT in thin film hetero-junction photodetector

Cited by 20 publications

References 57 publications

Enhancement in the transient visible light anisotropic photoresponse of cobalt‐incorporated tungsten diselenide ternary alloy

Enhancement in the transient visible light anisotropic photoresponse of cobalt‐incorporated tungsten diselenide ternary alloy

Dye‐sensitized solar cells based on nickel‐doped tungsten diselenide counter electrodes

Tunable Linearity of High‐Performance Vertical Dual‐Gate vdW Phototransistors

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