Polyimide-based ultraviolet-operated nonvolatile photomemory device

Abstract

Organic nonvolatile photomemory devices have drawn considerable attention in the field of optical computing. However, most organic nonvolatile photomemory devices use a charge-trap-type architecture that is complex and difficult to miniaturize. This paper proposes a nonvolatile polyimide (PI) resistive photomemory device with a simple metal–PI–metal configuration; its resistance can be altered using pulsed ultraviolet (UV) irradiation and can be maintained at the altered level even after irradiation has ceased. The resistance can also be returned to the initial state by subsequent irradiation with UV light. The memory window is around 7 order of magnitude. Fourier-transform infrared spectroscopy and UV–visible/near-infrared spectroscopy demonstrated that UV irradiation caused a high-energy-gap (Eg) aromatic form of PI to transform into low-Eg quinoid form, prompting the dominant conduction mechanism of the photomemory device to change from hopping conduction to ohmic conduction. A model characterizing the PI-based photomemory device was also developed and is discussed herein.