IGZO/PbS QD/Ga2O3-Based Optical Synapse Transistors with High PPF for NIR Detection

Abstract

In this paper, we present a high-PPF optical synapse transistor with an IGZO/PbS QD/Ga2O3 structure for NIR sensing applications. The fabricated device exhibited superior NIR detection capabilities, with responsivities of 214.5 ± 4.1, 202.4 ± 5.6, and 188.5 ± 5.8 A/W and high PPF indices of 195.2, 187.0, and 179.8% under 1080, 1300, and 1550 nm illumination at 0.1 mW/cm², respectively. The device also demonstrated modulation of synaptic plasticity, including a transition from STP to LTP with increasing stimulus intensity, pulse width, and pulse number, as well as potentiation with optical pulses and depression with electrical pulses. Furthermore, the device exhibited exceptionally low power consumption, as low as 3.67 pJ per event at 1550 nm. Finally, ANN simulations utilizing the measured device characteristics achieved a 90.16 % recognition accuracy. These results highlight the feasibility of IGZO/PbS QD/Ga2O3 optical synapse transistors for low-power, high-performance artificial vision systems based on NIR sensing.