Printed memory devices using electrohydrodynamic deposition technique

Abstract

This research utilizes electrohydrodynamic printing to fabricate a transparent memristor device having active film of zinc-oxide sandwiched between two silver cross-bar electrodes. It is a unique structure and never been reported in the literature before. The bipolar memristor device demonstrates current bistability as a result of the breakdown of zinc oxide layer into distinct doped and un-doped regions, thus resulting into swift charge transfer. The oxygen vacancies are created in the zinc-oxide layer upon receiving a minimum bias voltage (+ve/−ve) known as forming voltage. The maximum ON/OFF ratio of the current bi-stability for the fabricated memristor was as large as 1 × 103 which is considered satisfactory. The memristor device demonstrated a robust performance of up to 1000 read/write cycles. The printed device was characterized for the structural confirmation using x-ray diffraction analysis and it showed hexagonal wurtzite structure for ZnO active layer and typical face-centred cubic structure for the silver electrodes. The morphological uniformity was confirmed by scanning electron microscopy whereas > 90% transparency was reported by the optical characterization of the zinc-oxide active layer.