<italic>In Situ</italic> Study of Radiation Stability and Associated Conduction Mechanisms of Nb-Doped TiO2/p-Si Heterojunction Diode Under Swift Heavy Ion Irradiation

Abstract

In situ current–voltage characteristics of Nb-doped TiO2/p-Si-based heterojunction diode have been studied under dense electronic excitations of 84-MeV Si6+ ions. The diode parameters such as ideality factor ( $\eta $ ), barrier height ( $\phi _{B}$ ), reverse saturation current ( ${J}_{s}$ ), and series resistance ( ${R}_{s}$ ) are found to be a strong function of ion irradiation fluence. The observed anomalies of fluence dependence of barrier height and ideality factor are explained in terms of irradiation-induced created defects complexes, modification of interface states and structural properties of Nb-doped TiO2 (NTO) layer. Several mechanisms such as barrier height inhomogeneity, donor defects-induced enchantment in n-NTO layer conductivity, and various current conduction mechanisms involved at different voltage ranges are discussed as a function of fluence with the help of constructed energy band diagram. Such in situ studies on n-NTO/p-Si heterojunction diode under radiation harsh environment are very appropriate for the better understanding of heterojunction interface properties and make it suitable for use in aerospace industry and nuclear reactors.