Low bias operated, fast response SnSe thin film Vis-NIR photodetector on glass substrate using one-step thermal evaporation technique

Abstract

Photodetector application lies in the heart of wearable electronics like artificial visibility, smart watch, etc. Among the recently investigating materials, tin-selenide plays an active role. It has paved its way due to diverse field applicability like thermoelectric, gas sensing, etc. Here, the photodetection properties of SnSe film (in the visible and the IR region) deposited on the cheaper substrate soda-lime glass by one-step thermal evaporation technique are reported. For the IR radiation (1064 nm), the film showed a swift response/recovery time of 5/28 ms at 18 mW/cm2 power density and 300 mV bias voltage. For the visible radiation (532 nm), the device showed 9/34 ms response/recovery times at 32 mW/cm2 and 300 mV bias voltage. The carriers' dynamics are investigated using time-resolved photoluminescence (TRPL). TRPL studies showed no sign of the trap or defect states in the film. The different values of the exponent in the power-law fitting at different bias voltages indicated that the electron-hole recombination might be responsible for the low responstivity of such a device and not the trap states. Thus, the exact process responsible for low responstivity is determined. Through detailed characterization, the study showed the path for improvement in the performance of future photodetector devices.