Thin and thick films of metal oxides and metal phthalocyanines as gamma radiation dosimeters

Abstract

Numerous efforts were devoted to investigating the influence of radiation on metal oxides and polymer materials for dosimetry applications. Metal oxides, such as NiO, LaFeO 3 , CeO 2 , TeO 2 , In 2 O 3 , SiO and MnO, and polymers, such as CuPc, NiPc, MnPc and CoPc, were used as the active constituents in the fabrication of -radiation sensors. Thin and thick film devices were made in various topologies to form resistors, capacitors, pn-junctions and transistors. It was found that the properties of the active films (and, hence, their sensitivity to radiation) could be controlled by doping their constituent materials with carbon and mixing them in different proportions.The 60 Co and 137 Cs sources were used to expose the samples to -radiation. Current-voltage characteristics, optical absorption spectra, Raman spectra, SEM and XRD measurements were recorded for the samples after each exposure procedure and values of radiation damage were estimated.Thin film devices were found to be more sensitive to radiation than their thick film counterparts. Annealing was used to restore the properties of thick film devices after they were damaged with radiation. Thick films could be therefore reused on a repeatable basis, but thin film devices could not, as the heat treatments necessary for annealing were found to cause diffusion of the electrode materials.In this work, the possibility of fabricating a device that would satisfy the requirement of a particular application, such as sensitivity to -radiation and working dose region, was experimentally demonstrated. Based on the findings, these devices were found to provide a cost-effective alternative for room temperature real time -radiation dosimeter applications.Index Terms-Gamma radiation, metal oxides, metal phthalocyanines, MOS, optical and electrical properties, personal dosimeter, pn-junction, thin and thick films.

Effect of Gamma Irradiation on the Structural and Optical Properties of ZnO Thin Films

“…The most common representation are complex refractive index, n*, and complex dielectric constant Ɛ*. These two representations are related by [21]: n* = n + ik (7) Ɛ* = Ɛ r + iƐ i (8) Where n, k, Ɛ r and Ɛ i are refractive index (real part), extinction coefficient (imaginary part), real part of dielectric constant and imaginary part of dielectric constant respectively. The extinction coefficient k, describes the absorption of light as it travels through the absorption of light as it travels through the material can be calculated by the following equation [1,22]: Fig.…”

“…When solid material exposure to ionizing radiations produces changes in the microstructural properties of the material, which in turn affects the optical, electrical and other physical properties of the material [4][5][6]. Numerous efforts have recently been made to investigate the influence of gamma radiation on thin films and thin film structures of different metal oxides and polymers, in order to find out the suitability of using thin films and thin film structures of different metal oxides and polymers as gamma radiation dosimeters [7][8][9][10] . Physical properties of ZnO are strongly influenced by the growth parameters and the post deposition treatments [11].…”

Effect of gamma radiation on optical and electrical properties of tellurium dioxide thin films

“…Numerous efforts have recently been made to investigate the influence of gamma radiation on thin films and thin film structures of different metal oxides and polymers, in order to find out the suitability of using thin films and thin film structures of different metal oxides and polymers as gamma radiation dosimeters (Colby et al 2002;Arshak et al 2004. Naturally, a deep understanding of the physical properties of these thin films and thin film structures under the influence of gamma radiation is quite important from the viewpoint of design of novel and high sensitivity radiation dosimeters for gamma radiations.…”

Ultraviolet laser diodes grown on semipolar (202¯1) GaN substrates by plasma-assisted molecular beam epitaxy

“…1,2 The physical mechanism of detection was based on the fact that both electrical and optical properties of the materials experience changes upon the exposure to gamma radiation. 3 For instance, gamma rays can produce a change in the density of charge carriers in semiconducting material, which can be used for detection. 4,5 Although standoff detection is preferred, it is a challenging job.…”