Visible-light-mediated carrier type modulation at the LaAlO_3/SrTiO_3 interface

摘要

A LaAlO3/SrTiO3 (LAO/STO) heterointerface with the sheet charge density of electrons on the order of magnitude of 10(13) e/cm(2) was obtained by depositing a 10 unit-cell LAO layer on the TiO2-teminated STO substrate. An obvious persistent photoconductivity effect was observed for the as-prepared LAO/STO heterointerface. By way of Hall-like coefficient and magnetoresistance measurements at different light power intensities, it is demonstrated that the mechanism of magnetoresistance changes with the increase in light power density on the sample; more importantly, when the light power intensity is increased to a specific value, 270 mW in this case, the carrier type of the interface is tailored from n-type to p-type, which is probably ascribed to the photoinduced p-type hole dopants and has never been reported at the LAO/STO interface before, thus providing important insights into a controllable heterointerface for oxide-based thin film electronics.