Localised nanoscale resistive switching in GaP thin films with low power consumption

Abstract

Resistive switching behaviour is observed for GaP thin films. Conductive AFM and FORC-IV measurements show that the current is localised at grain boundaries. The switching mechanism is driven by Ga migration along the grain boundaries.

Optical Tuning of Resistance Switching in Polycrystalline Gallium Phosphide Thin Films

“…Figure 2 illustrates the filament formation and rupture under application of an external bias for the GaP system of interest. Previously, X-ray photoelectron spectroscopy (XPS) measurements on our GaP films confirmed the presence of peaks that correspond to metallic Ga. 31 We suggested these Ga-rich regions were localized to the grain boundaries and hence formed conductive channels in the ON state but at the time did not have any direct evidence. The cAFM images now shown in Figure 1b confirm this hypothesis; i.e., there are regions of high conductivity that correspond to the grain boundaries.…”

“…Furthermore, when we deposited a 50  50 m 2 Pt pad as the top electrode on the GaP/Si and tested the switching cycles, the VSET distribution is much narrower compared with the Pt-tip/GaP/Si device structure as shown in Figure 1d (lower panel). Based on our previous results, [28] we attribute this to a larger coverage area of the Pt top electrode, which accommodates more conductive filaments underneath. In this case, the VSET values are mainly distributed between 1.0 and 2.0 V bias, which is on par with the most up-to-date non-oxide resistive switching devices.…”

“…It builds on our previous work, in which we systematically investigated the origins of RS in polycrystalline GaP films. [28] Here we investigate if the RS characteristic can be tuned by an incident photon flux. First, we postulate on the plausible microstructural origins of RS in polycrystalline GB, namely Ga interstitials within grain boundaries (GBs).…”

“…However we have already shown that II-VI/III-V semiconductor films (e.g. ZnS, [36] GaP, [28] etc.) deposited by pulsed laser deposition contain defects, attributed to excess cations.…”

“…The filament resistance is the initial resistance when the filament begins to form, and thus it can be calculated from the generated current at low bias voltage (V low /I). 31 Figure 5b shows the change of the R ON / R OFF and R 0 as a function of photon energy. It can be seen that the R ON /R OFF is rather scattered, while interestingly, the R 0 shows a decrease with increasing photon energy.…”