Ultraviolet-C Photoresponsivity Using Fabricated TiO2 Thin Films and Transimpedance-Amplifier-Based Test Setup

• Published in: Sensors Vol. 22; no. 21; p. 8176
• Main Authors: Cadatal-Raduban, Marilou, Pope, Jade, Olejníček, Jiří, Kohout, Michal, Harrison, John A., Hasan, S. M. Rezaul
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 25.10.2022; MDPI
• Subjects: Chemical technology; Electrodes; Glass substrates; Optical properties; photoconductive detector; Radiation; Semiconductors; sensor; Sensors; Severe acute respiratory syndrome coronavirus 2; Spectrum analysis; thin film; Thin films; titanium dioxide; titanium dioxide; thin film; ultraviolet; UV-C; photoconductive detector; sensor; transimpedance amplifier; TP1-1185; transimpedance amplifier; Transistors; ultraviolet; UV-C; X-rays; Zinc oxides
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s22218176

We report on fabricated titanium dioxide (TiO2) thin films along with a transimpedance amplifier (TIA) test setup as a photoconductivity detector (sensor) in the ultraviolet-C (UV-C) wavelength region, particularly at 260 nm. TiO2 thin films deposited on high-resistivity undoped silicon-substrate at thicknesses of 100, 500, and 1000 nm exhibited photoresponsivities of 81.6, 55.6, and 19.6 mA/W, respectively, at 30 V bias voltage. Despite improvements in the crystallinity of the thicker films, the decrease in photocurrent, photoconductivity, photoconductance, and photoresponsivity in thicker films is attributed to an increased number of defects. Varying the thickness of the film can, however, be leveraged to control the wavelength response of the detector. Future development of a chip-based portable UV-C detector using TiO2 thin films will open new opportunities for a wide range of applications.