Self-heating-induced electrical and optical switching in high quality VO2 films controlled with current pulses

Self-heating (SH)-induced electrical and optical switching in high quality VO2 films grown by magnetron sputtering on a c-cut sapphire substrate has been investigated under various applied constant current pulses (I-D). The effect of SH on the behavior of electrical conductivity (sigma), optical transmittance ((T) over tilde), and film temperature (T) examined by applying a constant current pulse of various magnitudes with a pulse duration of five seconds (Delta t = 5 s) in VO2 films which were pre-heated to and stabilized at 57 degrees C, at the brink of insulator-to-metal transition (IMT). The SH effect that arose from the application of constant I-D pulses led to a significant increase in T and substantial changes in sigma and (T) over tilde. Observations showed that, depending on the magnitude of I-D, the sigma and (T) over tilde demonstrate strikingly different temporal behavior not only during the SH-induced IMT but also after the removal of I-D. The observed phenomena could be explained using a simple model based on percolation theory previously proposed for the present system. The outcome of the model is confirmed by the results of the structural IMT obtained by Raman micromapping.

Automated summary

The study investigated self-heating-induced electrical and optical switching in high quality VO2 films grown on a c-cut sapphire substrate, under various constant current pulses. Results showed that the application of constant current pulses caused significant changes in electrical conductivity, optical transmittance, and film temperature, with different temporal behaviors observed depending on the magnitude of the current pulses. The observed phenomena were explained using a simple model based on percolation theory, confirmed by structural insulator-to-metal transition results obtained from Raman micromapping.