Swift heavy ion irradiation induced negative differential resistance and transport of charge carriers in conducting polymer-metal oxide hybrids

Abstract

An intriguing phenomenon of the negative differential resistance (NDR) in conducting polymer-metal oxide hybrids is manifested upon measuring the In-situ current-voltage characteristics. Anomalous evolution of low current state leading to the electrical bistability has also been observed as an induced effect at low ion irradiation doses and explained by invoking ordering of the polymer chains and electric-field induced charge transfer mechanisms. Later, a disorder leading to damage is observed at higher doses by the diffusion of irradiation-induced electrically active free radicals and defect centers within the active region of the device. This leads to the device into a high current state of electrical bistability. Further, the observed NDR is attributed to the tunneling of carriers along with transient charging of molecular chains by trapping of charge carriers at the heterojunction interfaces induced by ion irradiation. It is further confirmed by anomalous response of voltage shifting in the conductance response upon incremented doses of irradiation. Efforts are envisaged to understand the processes of irradiation interactions and their influences on the transport of charge carriers by fitting experimental data using various conduction models such as Ohmic conduction, space-charge-limited conduction (SCLC), and trap-assisted SCLC. Thus, such low-cost and simple design devices have lots of potential applications for radiation harsh environments and could be easily integrated into the existing silicon-based technology.