Responsivity enhancement of TiO2 based UV photodetector by antimony doping

The excellent photoelectric properties, high stability, and low-cost fabrication have gained TiO2 tremendous attention as a cutting-edge material for various energy-related applications. However, the bandgap energy in the UV range and the low excited states of TiO2 have urged researchers to incorporate different dopant elements to optimize its properties. We demonstrated the effect of antimony (Sb) incorporation to TiO2 as UV photodetector using chemical bath deposition technique. The structural, optical, and electrical behaviour of undoped and doped devices (Sb:TiO2) were analyzed. Under UV irradiation at a wavelength of 365 nm and a power intensity of 130 μW, we achieved remarkable enhancement in device sensitivity. Compared to an undoped device (TiO2-Ns/PSi/Ag), the doped device (Sb:TiO2-Ns/PSi/Ag) demonstrated superior photoresponse and performance. The device exhibited Schottky characteristics within a voltage range of -5V to 5 V, demonstrating strong responsiveness and excellent electrical behaviour. I-V analysis at bias voltages of 3 V, and 5 V revealed outstanding responsivity and sensitivity. The best optimized performance device (Sb:TiO2-Ns/PSi/Ag) demonstrate highest photodetector parameters of responsivity as 23.5 A/W, quantum efficiency as ∼8 × 103%, sensitivity as 685.71 %, gain as 7.86, detectivity as 1.97 × 1012 Jones, and NEP as 9.0 × 10–14 W compared to that of the undoped TiO2 device (TiO2-Ns/PSi/Ag) with responsivity of 15.4 A/W, quantum efficiency as 5.22 × 103%, sensitivity as 420.81 %, gain as 5.21 detectivity as 1.25 × 1012 Jones, and NEP as 1.42 × 10–13 W, as a results of Sb incorporation to TiO2 both under UV light illumination (wavelength 365 nm and power intensity of 130 μW) at 5 V bias voltage. These findings underscore the significant impact of Sb doping on TiO2 for photodetection, leading to enhanced photo-responsivity and sensitivity compared to conventional TiO2-based devices, thereby establishing Sb:TiO2 structures as promising candidates for UV sensing applications.