Highly aligned indium zinc oxide nanowire-based artificial synapses with low-energy consumption

Ultralow-power optoelectronic synaptic transistors based on polyzwitterion dielectrics for in-sensor reservoir computing

Bio-inspired transistor synapses use solid electrolytes to achieve low-power operation and rich synaptic behaviors via ion diffusion and trapping. While these neuromorphic devices hold great promise, they still suffer from challenges such as high leakage currents and power consumption, electrolysis risk, and irreversible conductance changes due to long-range ion migrations and permanent ion trapping. In addition, their response to light is generally limited because of "exciton-polaron quenching", which restricts their potential in in-sensor neuromorphic visions. To address these issues, we propose replacing solid electrolytes with polyzwitterions, where the cation and anion are covalently concatenated via a flexible alkyl chain, thus preventing long-range ion migrations while inducing good photoresponses to the transistors via interfacial charge trapping. Our detailed studies reveal that polyzwitterion-based transistors exhibit optoelectronic synaptic behavior with ultralow-power consumption (~250 aJ per spike) and enable high-performance in-sensor reservoir computing, achieving 95.56% accuracy in perceiving the trajectory of moving basketballs.

Solution Process-Based Thickness Engineering of InZnO Semiconductors for Oxide Thin-Film Transistors with High Performance and Stability

To fabricate oxide thin-film transistors (TFTs) with high performance and excellent stability, preparing high-quality semiconductor films in the channel bulk region and minimizing the defect states in the gate dielectric/channel interfaces and back-channel regions is necessary. However, even if an oxide transistor is composed of the same semiconductor film, gate dielectric/channel interface, and back channel, its electrical performance and operational stability are significantly affected by the thickness of the oxide semiconductor. In this study, solution process-based nanometer-scale thickness engineering of InZnO semiconductors was easily performed via repeated solution coating and annealing. The thickness-controlled InZnO films were then applied as channel regions, which were fabricated with almost identical film quality, gate dielectric/channel interface, and back-channel conditions. However, excellent operational stability and electrical performance suitable for oxide TFT backplane was only achieved using an 8 nm thick InZnO film. In contrast, the ultrathin and thicker films exhibited electrical performances that were either very resistive (high positive VTh and low on-current) or excessively conductive (high negative VTh and high off-current). This investigation confirmed that the quality of semiconductor materials, solution process design, and structural parameters, including the dimensions of the channel layer, must be carefully designed to realize high-performance and high-stability oxide TFTs.