Self-Biased and Biased Photo-Sensitivity of Tin Mono-Selenide (Snse) Photonic Crystal Photodetector Under Poly/Monochromatic Light

Recently, transition metal chalcogenides were found to be the most promising candidates for photosensor- and photodetector-based applications. This study reports the photodetection and response properties of tin selenide (SnSe) crystals grown by the direct vapour transport (DVT) technique. The basic properties of SnSe have been reported in a previous article. Photodetection properties are investigated using polychromatic or monochromatic light of varying intensities and bias voltages. Results depict that detectors work congenially under monochromatic sources of light. It is observed that responsivity (Rλ) is higher for red, while detectivity and sensitivity are observed to be maximum for blue light under the self-biased (no bias) condition. The results observed under varying intensity (spot size) in the absence of biassing suggest that as intensity rises, all the parameters of the photodetector are also rising, while at constant intensity (30 mW/cm2), by varying the bias voltage, the detectivity of red light is decreasing due to an increment in dark current. Photodetectors are more efficient at converting optical signals to electrical signals, and their sensitivity is colour-dependent. Mainly, it is observed that monochromatic light shows high sensitivity to low bias voltages, while polychromatic light shows high sensitivity to high voltages. Observed results point to the detection of both monochromatic and polychromatic light by the fabricated detector, which can be applied to SnSe-based devices. A device can be used to fabricate colour and intensity detection.