Photothermal Engineering in Ta₂O₅ Memristors: Blue-Laser-Driven Filament Reorientation for On/Off Ratio Enhancement

This work demonstrates the first instance of wavelength-selective resistive switching (RS) activation in Ag/Ta₂O₅/ITO memristors via photothermal engineering, revealing that photon-matter interactions govern conductive filament (CF) dynamics, a critical insight for advancing memristor-based neuromorphic computing architectures. The photothermal effects of 405, 532, and 790 nm laser irradiation are conducted through current-voltage (I-V) characterization, 100-cycle on/off ratio evaluation, and retention time analysis. Remarkably, the device subjected to 405 nm laser irradiation (300 s, 1.2 mW) exhibits an unprecedented on/off ratio of 93, a retention time above 10⁴ s, and a maximum current of 2 mA, representing nearly a 10-fold RS enhancement compared to the pristine device. Finite element thermal simulations and laser power-dependent RS analysis elucidate that the laser-induced CF formation arises from localized photothermal heating, enabling precise control over device performance.