Negative differential resistance behavior in a single-crystalline vanadium dioxide nanobeam without epitaxial interfacial strain

Abstract

We investigate the current-dependent negative differential resistance (NDR) behavior in a single-crystalline vanadium dioxide (VO2) nanobeam without epitaxial interfaces. VO2 nanobeams are grown out of the basal r plane of sapphire and then mechanically transferred onto an oxidized silicon substrate using a stamping transfer technique. Interestingly, compared to a previous report on an epitaxially grown VO2 nanobeam with a strong adhesion strain at interfaces, the transferred VO2 nanobeam without epitaxial interfaces exhibits distinctly different NDR phenomena. We observe three different NDR behaviors along with the appearance of an intermediate M2 phase in the current–voltage (I–V) characteristics of the transferred VO2 nanobeam device obtained using the current-sweeping mode. This result is well supported by temperature-dependent Raman spectra and corresponding optical microscope images showing the appearance of an intermediate M2 phase and the spatial distribution of insulating and metallic domains along the length of the transferred nanobeam without epitaxial interfaces, which is likely attributed to different surface stresses, including interfacial stress.