Performance Assessment of a New Radiation Dosimeter Based on Carbon Nanotube Field-Effect Transistor: A Quantum Simulation Study

Abstract

In this paper, the performance of a new nanoscale radiation sensitive field-effect transistor (RADFET) based on carbon nanotube (CNT) is investigated using an atomistic simulation approach. The proposed radiation nanosensor uses the radiation-induced interface trapped charges as a sensing mechanism, and it is endowed with the coaxial gate and the CNT-based sensitive channel. The quantum simulations are carried out using the non-equilibrium Green’s function formalism with self-consistent electrostatics assuming a ballistic transport. The threshold voltage shift is considered as a sensing metric. A comprehensive RADFET simulation that includes the electrostatic potential, charge density, $I_{\mathrm {DS}}$ – $V_{\mathrm {GS}}$ characteristics, and sensitivity behavior, has been performed. In addition, a parametric study has been done in order to explore the impact of change in the dosimeter geometrical parameters on the RADFET sensitivity. It has been found that the proposed radiation sensor is effective and its sensitivity can be further improved using thicker silicon dioxide layer and longer CNT diameters. The obtained results make the proposed CNT-based RADFET as a promising candidate for high-performance radiation sensing applications, especially for in vivo dosimetry, where the development of new nanodosimeters is in dire need.