We report on transport measurements under optical stimulation of persistent photoconductance (PPC) at the interface between amorphous LaAlO3 films and SrTiO3 crystals. The spectral response in the visible region was analyzed under varying illumination conditions and exposure times down to milliseconds. The PPC is plastically modulated by optical stimuli of varying strength and duration, demonstrating fine-tuned photoconductive responsivity over a diversity of cumulated timespans. Interestingly, under optimal conditions, the photoconductance is sensitive to intensity contrasts under conditions comparable to bright-sunlight environments. The prospects of exploiting photoconductance—including potential strategies to reach higher sensitivity—are discussed in the context of neuromorphic applications.

This work was supported by the Spanish Ministerio de Ciencia, Innovacion y Universidades through Grants No. MAT2017- ́ 85232-R (AEI/FEDER, UE), and Severo Ochoa SEV-2015- 0496, and the Generalitat de Catalunya through Grant No. 2017 301 SGR1377. We acknowledge collaboration and discussions with Dr. Florencio Sanchez regarding thin ́ film growth. Y C. acknowledges the China Scholarship Council grant n° 201506890029. This work is part of the Ph.D. thesis of Y.C.

Peer reviewed