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.

Center for Research in Analog and VLSI Microsystem Design Massey University Auckland 0632 New Zealand

Department of Low Temperature Plasma Institute of Physics of the Czech Academy of Sciences Na Slovance 1999 2 182 21 Prague 8 Czech Republic

Institute of Laser Engineering Osaka University 2 6 Yamadaoka Suita 565 0871 Osaka Japan

School of Natural Sciences Massey University Auckland 0632 New Zealand

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