**Author details**

*Integrated Circuits/Microchips*

electrodes larger than 2 mm<sup>2</sup>

electrical response of the material.

response to ionizing radiation.

**4. Conclusions**

area samples is 175 nC Gy<sup>−</sup><sup>1</sup>

film thickness of crystals has minor influence on the sensitivity for a device with

Fraboni and co-workers proposed a model to explain the photocurrent signal induced by X-ray radiation (**Figure 7**) [28]. The model described the accumulation of holes in the LUMO level with the X-ray radiation. Radicals generated from the X-rays radiation activated energy levels within the HOMO and LUMO levels where electrons were trapped. The induced holes in the LUMO level induce an increase in the photoconductivity easily measurable due to the high sensitivity to X-rays and

Organic field effect transistors are new but very potential devices to be used as ionization radiation dosimeters. Different parameters like off current, on current, threshold voltage, current ratio and sub-threshold swing can be monitored as a function of ionizing radiation dose. Organic field effect transistors are capable of providing a tissue equivalent response to ionizing radiation. High Z counterparts, such as insulating layer and metal electrodes can be fabricated making use of organic dielectrics and conducting polymers (PEDOT:PSS or others), respectively. Moreover, organic materials possess outstanding properties, such as large area processing on lightweight and flexible substrates and ability to chemically tailor their properties. In particular, lightweight, flexible OFETs can be attached to the patient during the radiation treatment with possibility to read out parameters after treatment or operating transistors at very low voltages. For sure more work should be done on sensitivity improvement and characterization of such dosimeters. For example, it is important to check their linearity, energy and dose rate dependence, and so on. The sensitivity of such dosimeters can be improved by increasing the trap carrier density in organic semiconductor or dielectric layers. Similar to organic memory devices dielectric layer can be complex or with floating gate to store more charges and thus show the improved

[27].

. The maximum obtained sensitivity for large electrode

**122**

Irina Valitova1 , Zhihui Yi2 and Jonathan Sayago3 \*

1 Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, Canada

2 PhDs Network Inc., Toronto, Canada

3 Instituto de Energías Renovables, Universidad Nacional Autónoma de México, Temixco, Morelos, México

\*Address all correspondence to: jjsayago@ier.unam.mx

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
