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The growth of layered 2D compounds is a key ingredient in finding new phenomena in quantum materials, optoelectronics, and energy conversion. Here, we report SnP2Se6, a van der Waals chiral (R3 space group) semiconductor with an indirect bandgap of 1.36 to 1.41 electron volts. Exfoliated SnP2Se6flakes are integrated into high-performance field-effect transistors with electron mobilities >100 cm2/Vs and on/off ratios >106at room temperature. Upon excitation at a wavelength of 515.6 nanometer, SnP2Se6phototransistors show high gain (>4 × 104) at low intensity (≈10−6W/cm2) and fast photoresponse (< 5 microsecond) with concurrent gain of ≈52.9 at high intensity (≈56.6 mW/cm2) at a gate voltage of 60 V across 300-nm-thick SiO2dielectric layer. The combination of high carrier mobility and the non-centrosymmetric crystal structure results in a strong intrinsic bulk photovoltaic effect; under local excitation at normal incidence at 532 nm, short circuit currents exceed 8 mA/cm2at 20.6 W/cm2.
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Anisotropic Properties of Quasi‐1D In 4 Se 3 : Mechanical Exfoliation, Electronic Transport, and Polarization‐Dependent Photoresponse
Abstract Theoretical and experimental investigations of various exfoliated samples taken from layered In4Se3crystals are performed. In spite of the ionic character of interlayer interactions in In4Se3and hence much higher calculated cleavage energies compared to graphite, it is possible to produce few‐nanometer‐thick flakes of In4Se3by mechanical exfoliation of its bulk crystals. The In4Se3flakes exfoliated on Si/SiO2have anisotropic electronic properties and exhibit field‐effect electron mobilities of about 50 cm2 V−1 s−1at room temperature, which are comparable with other popular transition metal chalcogenide (TMC) electronic materials, such as MoS2and TiS3. In4Se3devices exhibit a visible range photoresponse on a timescale of less than 30 ms. The photoresponse depends on the polarization of the excitation light consistent with symmetry‐dependent band structure calculations for the most expectedaccleavage plane. These results demonstrate that mechanical exfoliation of layered ionic In4Se3crystals is possible, while the fast anisotropic photoresponse makes In4Se3a competitive electronic material, in the TMC family, for emerging optoelectronic device applications.
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- Award ID(s):
- 1740136
- PAR ID:
- 10446827
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 31
- Issue:
- 52
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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