Optically Reconfigurable Complementary Logic Gates Enabled by Bipolar Photoresponse in Gallium Selenide Memtransistor

To avoid the complexity of the circuit for in-memory computing, simultaneous execution of multiple logic gates (OR, AND, NOR, and NAND) and memory behavior are demonstrated in a single device of oxygen plasma-treated gallium selenide (GaSe) memtransistor. Resistive switching behavior with R-ON/R-OFF ratio in the range of 10(4) to 10(6) is obtained depending on the channel length (150 to 1600 nm). Oxygen plasma treatment on GaSe film created shallow and deep-level defect states, which exhibit carriers trapping/de-trapping, that lead to negative and positive photoconductance at positive and negative gate voltages, respectively. This distinguishing feature of gate-dependent transition of negative to positive photoconductance encourages the execution of four logic gates in the single memory device, which is elusive in conventional memtransistor. Additionally, it is feasible to reversibly switch between two logic gates by just adjusting the gate voltages, e.g., NAND/NOR and AND/NAND. All logic gates presented high stability. Additionally, memtransistor array (1x8) is fabricated and programmed into binary bits representing ASCII (American Standard Code for Information Interchange) code for the uppercase letter N. This facile device configuration can provide the functionality of both logic and memory devices for emerging neuromorphic computing.

Automated summary

To simplify in-memory computing circuits, researchers have developed a single device that can simultaneously perform multiple logic gates and memory behaviors. This device, made of oxygen plasma-treated gallium selenide, exhibits resistive switching behavior and can achieve high stability and versatility. By adjusting gate voltages, the device can switch between NAND/NOR and AND/NAND logic gates, making it a promising solution for emerging neuromorphic computing applications.