Palladium Nanoparticle Enhanced Giant Photoresponse at LaAlO₃/SrTiO₃ Two-Dimensional Electron Gas Heterostructures

With LaAlO3 surface modification by Pd nanoparticles, LaAlO3/SrTiO3 (LAO/STO) interfacial two-dimensional electron gas presents a giant optical switching effect with a photoconductivity on/off ratio as high as 750% under UV light irradiation. Pd nanoparticles with a size around 2 nm are deposited on top of the LAO surface, and the LAO/STO interface exhibits a giant response to UV light with a wavelength shorter than 400 nm. This giant optical switching behavior has been explained by the Pd nanoparticle's catalytic effect and surface/interface charge coupling.