Titanium dioxide thin films as vacuum ultraviolet photoconductive detectors with enhanced photoconductivity by gamma-ray irradiation

Cadatal-Raduban, Marilou; Yamanoi, Kohei; Olejníček, J.; Kohout, Michal; Kato, Seiya; Horiuchi, Yusuke; Kato, Takumi; Yu, Hang; Sarukura, Nobuhiko; Ono, Shingo

doi:10.1016/j.tsf.2021.138637

Cited by 8 publications

(6 citation statements)

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“…Furthermore, we also investigate the improvement of its photoconductivity in the VUV region using TiO 2 thin films deposited on high resistivity undoped silicon (Si), quartz glass (SiO 2 ), and soda lime glass (SLG) substrates with thicknesses of 80 nm, 500 nm, and 1000 nm. Our results show that TiO 2 thin films in general—but especially TiO 2 thin films deposited on SiO 2 substrate with a thickness of 80 nm exhibit higher photoconductivity, with photocurrents reaching the milli-Ampere range, compared with our previous works using wide band gap fluorine-based insulator thin film photoconductive detectors [ 26 , 27 ] and gamma-ray irradiated detectors, based on amorphous TiO 2 on SLG substrate [ 28 ]. The potential of using TiO 2 thin films as photoconductive detectors of VUV radiation will contribute to the enhancement of the many applications of this high energy radiation.…”

Section: Introductionmentioning

confidence: 50%

“…The photoconductivity of the thin film detectors was evaluated by illuminating their surface with a VUV lamp (Hamamatsu Photonics, Hamamatsu, Japan) emitting at a peak wavelength of 160 nm [ 28 ] and a radiant intensity of about 1.4 μW cm −2 mm −1 at a distance of 50 cm from the lamp. While applying a bias voltage of up to 100 V across the Al electrodes, the photocurrent produced by the photo-generated carriers as they drifted towards the Al electrodes was measured using an ultra-high-resistance electrometer (ADCMT 8340A, Hamamatsu, Japan).…”

Section: Methodsmentioning

confidence: 99%

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Effect of Substrate and Thickness on the Photoconductivity of Nanoparticle Titanium Dioxide Thin Film Vacuum Ultraviolet Photoconductive Detector

et al. 2021

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Vacuum ultraviolet radiation (VUV, from 100 nm to 200 nm wavelength) is indispensable in many applications, but its detection is still challenging. We report the development of a VUV photoconductive detector, based on titanium dioxide (TiO2) nanoparticle thin films. The effect of crystallinity, optical quality, and crystallite size due to film thickness (80 nm, 500 nm, 1000 nm) and type of substrate (silicon Si, quartz SiO2, soda lime glass SLG) was investigated to explore ways of enhancing the photoconductivity of the detector. The TiO2 film deposited on SiO2 substrate with a film thickness of 80 nm exhibited the best photoconductivity, with a photocurrent of 5.35 milli-Amperes and a photosensitivity of 99.99% for a bias voltage of 70 V. The wavelength response of the detector can be adjusted by changing the thickness of the film as the cut-off shifts to a longer wavelength, as the film becomes thicker. The response time of the TiO2 detector is about 5.8 μs and is comparable to the 5.4 μs response time of a diamond UV sensor. The development of the TiO2 nanoparticle thin film detector is expected to contribute to the enhancement of the use of VUV radiation in an increasing number of important technological and scientific applications.

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Section: Introductionmentioning

confidence: 50%

Section: Methodsmentioning

confidence: 99%

Effect of Substrate and Thickness on the Photoconductivity of Nanoparticle Titanium Dioxide Thin Film Vacuum Ultraviolet Photoconductive Detector

et al. 2021

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“…Moreover, the luminescence intensity increased, while the transmittance decreased as the films became thicker. The luminescence emission can therefore be attributed to the radiative recombination of electrons in deep traps and holes in the valence band [ 30 , 33 , 34 , 35 , 36 , 37 , 38 ]. The increase in the luminescence intensity confirms that thicker films have more defect states.…”

Section: Resultsmentioning

confidence: 99%

“…In this paper, we explore the photoconductivity of titanium dioxide (TiO 2 ) thin films in the UV-C wavelength region, especially with 260 nm wavelength excitation. Mostly known for its UV photocatalytic activity, TiO 2 has excellent chemical, physical, and optical properties including being a wide band-gap semiconductor [ 29 , 30 ]. Compared with ZnO, GaN, AlN, and BN, TiO 2 is relatively easier and cheaper to fabricate.…”

Section: Introductionmentioning

confidence: 99%

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

Cadatal-Raduban

Pope

Olejníček

et al. 2022

Sensors

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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.

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“…Marilou et al used pure titanium as a target material for VUV radiation photodetectors [ 12 ]. They prepared TiO 2 films by reactive DC magnetron sputtering on the surface of soda lime glass (SLG) microscope slide substrates.…”

Section: Optoelectrical Application Based On Tio 2 ...mentioning

confidence: 99%

A Review on the Progress of Optoelectronic Devices Based on TiO2 Thin Films and Nanomaterials

Sang

Yao

et al. 2023

Nanomaterials

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Titanium dioxide (TiO2) is a kind of wide-bandgap semiconductor. Nano-TiO2 devices exhibit size-dependent and novel photoelectric performance due to their quantum limiting effect, high absorption coefficient, high surface-volume ratio, adjustable band gap, etc. Due to their excellent electronic performance, abundant presence, and high cost performance, they are widely used in various application fields such as memory, sensors, and photodiodes. This article provides an overview of the most recent developments in the application of nanostructured TiO2-based optoelectronic devices. Various complex devices are considered, such as sensors, photodetectors, light-emitting diodes (LEDs), storage applications, and field-effect transistors (FETs). This review of recent discoveries in TiO2-based optoelectronic devices, along with summary reviews and predictions, has important implications for the development of transitional metal oxides in optoelectronic applications for researchers.

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Titanium dioxide thin films as vacuum ultraviolet photoconductive detectors with enhanced photoconductivity by gamma-ray irradiation

Cited by 8 publications

References 35 publications

Effect of Substrate and Thickness on the Photoconductivity of Nanoparticle Titanium Dioxide Thin Film Vacuum Ultraviolet Photoconductive Detector

Effect of Substrate and Thickness on the Photoconductivity of Nanoparticle Titanium Dioxide Thin Film Vacuum Ultraviolet Photoconductive Detector

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

A Review on the Progress of Optoelectronic Devices Based on TiO2 Thin Films and Nanomaterials

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