High-temperature solid-state synthesis of Nb2SiTe4 nanosheets and their photoelectric performance in broadband self-powered photodetectors

Abstract

Nb₂SiTe₄, a layered narrow-bandgap van der Waals semiconductor, has attracted increasing attention due to its high carrier mobility and excellent optical absorption properties. In this study, we exploited this material in a photoelectrochemical (PEC) type photodetector (PD) to investigate its potential for energy saving optoelectronics. A simple high-temperature solid-state reaction method was utilized for synthesizing high quality Nb₂SiTe₄ crystals, and liquid-phase exfoliation (LPE) was employed to prepare the corresponding nanosheets for device construction. The photoelectric performances of the Nb₂SiTe₄ nanosheet PDs were characterized in a three-electrode system and broad spectral responses ranging from 400 to 900 nm were detected. The effects of dispersants, electrolyte, as well as light power density on the device performance were systematically investigated. At 0 V bias voltage, an optimal performance of the PDs was obtained in an acidic testing environment upon illumination of the 400 nm light, and the highest photocurrent density of 0.72 µA cm⁻² and responsivity of 7.71 µA W⁻¹ were achieved. Besides, the device demonstrated fine long-term cycling and air stabilities. This work implies the potential of Nb₂SiTe₄ for application in broadband photodetection of self-powering devices.