Pressure-enhanced optoelectronic properties in the two-dimensional metal phosphorus trichalcogenide semiconductor SnPSe3

Abstract

Pressure engineering in two-dimensional semiconductor materials, represented by metal phosphorus trichalcogenides (MPTs), has successfully induced diverse novel physical phenomena such as spin-crossover, volume collapse, piezochromism, metallization, and superconductivity. As a typical member of the MPT family, SnPSe₃ exhibits exceptional pressure responses, e.g., structural phase transitions, shrinkage of band gap, metallization and superconductivity. However, there is a lack of study on the optoelectronic performance under pressure, which may promote the exploration of high-performance MPT-based photodetectors. Here, the remarkably improved optoelectronic properties of SnPSe₃ with high photocurrent density J_ph (8.6 × 10⁴ μA cm⁻²), responsivity R (4.2 × 10⁵ μA W⁻¹), and external quantum efficiency (EQE) (8.4 × 10⁵) are obtained via introducing pressure, which represent almost three orders of magnitude increment compared to the initial values. Combining high-pressure UV-vis absorption and Raman spectral measurements, as well as theoretical calculations, i.e., electronic band structure, electron localization function and Bader charge, it was found that the pressure-enhanced photoelectric properties are mainly associated with the decrease of interatomic distances and the enhancement of interatomic interactions between P–P atoms as well as P–Se atoms, which promotes charge transfer and eventually leads to photocurrent improvement in compressed SnPSe₃. The discovery of pressure-enhanced optoelectronic properties in SnPSe₃ offers an effective means of regulating photoelectric properties and stimulates the exploration of the novel properties of two-dimensional semiconductors.