White-light-induced disruption of nanoscale conducting filament in hafnia

摘要

Nanoscale conducting filament, which forms the basis of the HfO_2 resistive memory, is shown to exhibit a "negative photoconductivity" behavior, in that, electrical conduction through it can be disrupted upon white-light illumination. This behavior should be contrasted against the positive photoconductivity behavior commonly exhibited by oxides or perovskites having narrower bandg-aps. The negative photoconductivity effect may be explained in terms of a photon-induced excitation of surrounding oxygen ions, which leads to migration and subsequent recombination with vacancies in the conducting filament. The finding suggests possible electrical-cum-optical applications for HfO_2-based devices, whose functionality is limited to-date by electrical stimulation.