Bulk photovoltaic effect and high mobility in the polar 2D semiconductor SnP<sub>2</sub>Se<sub>6</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39083609.
- Also identified by DOI 10.1126/sciadv.ado8272 and PMC identifier 11290483.
- Licence recorded as CC BY-NC.
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Abstract
The growth of layered 2D compounds is a key ingredient in finding new phenomena in quantum materials, optoelectronics, and energy conversion. Here, we report SnP<sub>2</sub>Se<sub>6</sub>, a van der Waals chiral (<i>R</i>3 space group) semiconductor with an indirect bandgap of 1.36 to 1.41 electron volts. Exfoliated SnP<sub>2</sub>Se<sub>6</sub> flakes are integrated into high-performance field-effect transistors with electron mobilities >100 cm<sup>2</sup>/Vs and on/off ratios >10<sup>6</sup> at room temperature. Upon excitation at a wavelength of 515.6 nanometer, SnP<sub>2</sub>Se<sub>6</sub> phototransistors show high gain (>4 × 10<sup>4</sup>) at low intensity (≈10<sup>-6</sup> W/cm<sup>2</sup>) and fast photoresponse (< 5 microsecond) with concurrent gain of ≈52.9 at high intensity (≈56.6 mW/cm<sup>2</sup>) at a gate voltage of 60 V across 300-nm-thick SiO<sub>2</sub> dielectric 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/cm<sup>2</sup> at 20.6 W/cm<sup>2</sup>.