Optical sensing and computing memory devices using nanostructured WO3

Abstract

This paper presents microfabrication, characterization, optical sensing and memory testing using nanostructured tungsten trioxide (WO3). Different experiments were performed to realize the integrated sensing and computing memory (ISCM) functionality on the same device. These ISCM devices were fabricated using standard wafer-scale microfabrication processes on 2-inch silicon (Si) substrate. First, the devices were tested to detect the broad wavelength spectrum ranging ultraviolet (UV) to near infrared (NIR). These photosensing devices were shown repeatable, reproducible and reliable results with fast switching speed (rise time (0.05 s)/fall time (0.08 s)) at 880 nm. Further, the memory functionality was realized using the electrical and optical stimuli at room temperature. The optically stimulated device has shown higher sensitivity for 880 nm and mimics the human brain's functional characteristics. The developed ISCM devices have shown enhanced performance parameters like paired pulse facilitation (PPF) index 171.2 %, retention time 300 s, resistance switching ratio 1.5 × 102 over electrical stimulation. The tested devices are able to demonstrate ISCM features and the developed process pathway for mass production.