Investigating the thickness-effect of free-standing high aspect-ratio TiO2 nanotube layers on microwave-photoresponse using planar microwave resonators

Alijani, Mahnaz; Wiltshire, Benjamin D.; Sopha, Hanna Ingrid; Sarpanah, Zahra; Mistrík, Jan; Hromádko, Luděk; Zarifi, Mohammad H.; Macák, Jan

Investigating the thickness-effect of free-standing high aspect-ratio TiO2 nanotube layers on microwave-photoresponse using planar microwave resonators

Files

1s2.0S2352940723001026main.pdf(9.15 MB)

Date

2023-06-01

Authors

Alijani, Mahnaz

Wiltshire, Benjamin D.

Sopha, Hanna Ingrid

Sarpanah, Zahra

Mistrík, Jan

Hromádko, Luděk

Zarifi, Mohammad H.

Macák, Jan

ORCID

0000-0003-1117-9854

0000-0001-7091-3022

Publisher

Elsevier

Altmetrics

Abstract

One-dimensional TiO2 nanotube (TNT) layers are a promising candidate for UV detection due to their distinctive anisotropic geometry which is effective for light harvesting and rapid carrier transport. Here, the photosensitivity efficiency of TNT layers with various thicknesses of 15, 50, 80, and 110 mu m was utilized at a microwave frequency regime by modeling and experimentally. A planar microwave split ring resonator (PMSRR) was designed and fabricated to operate at -8 GHz to study TNT layers by monitoring the scattering parameter (S21) of the PMSRR under a constant UV irradiation power of -96.4 mu W/cm2. According to the results, the 80 mu m thick TNT layers demonstrated the highest resonant amplitude variation for the customized PMSRR. The change of the resonant amplitude was mainly attributed to the conductivity variation contributed by perturbation of trapped electron concentration, as the dominant factor under UV illumination, and their electromagnetic wave interaction. The main advantage of the proposed method of PMSRR for microwave photosensitivity monitoring over the conventional direct current (DC) conductivity measurements is to eliminate the effect of contact resistance between the TNT layers and metal electrodes utilizing the contactless aspect of wave interactions with the TNT layers at microwave regime to perform electrode-less measurements.

Keywords

Planar microwave resonator, TiO2, Nanotube, Real-time microwave sensing, UV detection

Citation

Applied Materials Today. 2023, vol. 32, issue 1, p. 1-10.
https://www.sciencedirect.com/science/article/pii/S2352940723001026

Document type

Peer-reviewed

Document version

Published version

Language of document

en

Document licence

Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/