Development of ultra-sensitive broadband photodetector: a detailed study on hidden photodetection-properties of TiS2 nanosheets

We report an ultra-sensitive broadband photodetector based on horizontally aligned titanium disulfide nanosheets (TNs). Firstly, TNs were synthesized using the chemical vapor transport (CVT) technique to develop the photodetector, and then as-prepared TNs were deposited horizontally aligned between the interdigitated electrodes (IDEs) using the dielectrophoresis (DEP) technique. The photodetection performance of the as-prepared photodetector was analysed by illuminating the device with different wavelength low-power LED lights. The sensitivity of the as-developed photodetector has been studied for varying wavelength range (375 nm, 405 nm, 455 nm, 617 nm, 855 nm, 1050 nm) as well as for different power densities of individual incident lights. The as-developed photodetector shows high photoresponse for all mentioned wavelengths and shows a rapid response (10s) and recovery (10s) with ultra-high responsivity (1.174 × 104 AW−1), quantum efficiency (3.20 × 104 AW−1nm−1) as well as detectivity (3.039 × 1011 Jones) for 455 nm wavelength and 0.086 mW/mm2 power density of incident light. The ON/OFF ratio of the as-developed photodetector is found ultra-high i.e. 28.54. Its performance with respect to external bias voltage has also been studied and reported in the manuscript. The as-prepared TNs based photodetector shows many advantageous features like high stability and repeatability. The demonstrated ultra-sensitive photoresponse of as-prepared photodetector suggests the effectiveness of TNs for improving the characteristics of modern optoelectronic devices.