Exploiting the properties of TiO2 thin films as a sensing layer on (MEMS)-based sensors for radiation dosimetry applications

Khaled Shamma,Abdullah Aldwayyan,Hamad Albrithen,Abdullah Alodhayb

doi:10.1063/5.0032353

Abstract

In this work, we investigate the potential of exploiting TiO2 thin films as sensing layers on silicon micro-electromechanical systems for the detection of gamma radiations. All samples are exposed to gamma rays produced by 60Co, with different doses ranging from 0 kGy to 40 kGy. Properties of silicon coated with a 200-nm-thick layer of TiO2 grown at 200 °C by atomic layer deposition are studied before and after its gamma irradiation using x-ray diffraction (XRD), scanning electron microscopy, and spectroscopic ellipsometry. Atomic force microscopy (AFM) is carried out on functionalized microcantilevers to measure the resonance frequency shift (Δf 0) resulting from irradiation of the TiO2 thin film. XRD results show a change in the films from a mixture of rutile and anatase phases to an anatase phase upon irradiation. Spectroscopic ellipsometry results show a change with a fixed pattern in the film thickness, roughness, void, and optical constants with different irradiation doses. This pattern appears as Δf 0 in AFM, where the response of sensors to doses between 0 kGy and 20 kGy was linear. The values of Δf 0 are convenient to control parameters for the proposed dosimeter, which is characterized by the reproducibility and sensitivity of measurements. The maximum detectable linear effect of the proposed dosimeter was found at a dose of 20 kGy. This makes a 200-nm thin layer of TiO2 coated on a microcantilever surface, a possible candidate for dosimetry for the range lower than 20 kGy applications, such as in personal dosimeters.

Highlights

Micro-Electro-Mechanical Systems (MEMS) have recently witnessed major development in many fields
This reduction in grain size with (001) orientation is attributed to the fact that (001) anatase-TiO2 relaxed surface energy is considered among the highest formation energy surfaces in comparison with the other relaxed surfaces as reported by Lazzeri et al.,78 as calculated by density functional theory using the Perdew–Burke–Ernzerhof exchange(PBE)-correlation functional and local density approximation (LDA)
We have investigated the use of TiO2 thin films on (MEMS)-based cantilevers as sensing layers for dosimetric applications of gamma radiation in the range of 0 kGy–40 kGy

Summary

INTRODUCTION

Micro-Electro-Mechanical Systems (MEMS) have recently witnessed major development in many fields. We use a TiO2 thin film as a probe layer on MEMS-based cantilevers as sensors for gamma detection. Despite the presence of such techniques that show high sensitivity, there is an ongoing significant demand for developing practical, accurate, and portable devices for the detection of nuclear radiation. Due to their appealing characteristics, MEMS-based sensors are used in this work in the hopes of developing alterative techniques that could be low cost, easy to use, and portable for the detection of gamma radiation. The atomic layer deposition technique (ALD) has been used in the deposition of TiO2 thin films on substrates due to its intrinsic advantages, such as sub-nanometer precision in material thickness, high-quality thin-film production, and excellent atomic-level control of layer uniformity. We, investigate the potential of using TiO2-coated microcantilevers for the detection of gamma radiation

EXPERIMENTAL

RESULTS AND DISCUSSION

CONCLUSION