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

• Published in: Advanced science 2023-06, Vol.10 (17), p.e2205383-n/a
• Main Authors: Rehman, Shania, Khan, Muhammad Asghar, Kim, Honggyun, Patil, Harshada, Aziz, Jamal, Kadam, Kalyani D., Rehman, Malik Abdul, Rabeel, Muhammad, Hao, Aize, Khan, Karim, Kim, Sungho, Eom, Jonghwa, Kim, Deok‐kee, Khan, Muhammad Farooq
• Format: Article
• Language: English
• Subjects: Boolean; Brain; charge trapping; Electrodes; Electrons; gallium selenide; logic gates; Memory; memtransistors; Microscopy; Plasma; resistive switching; Selenium; Semiconductors; Spectrum analysis; Thin films; Transistors
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202205383

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 RON/ROFF ratio in the range of 104 to 106 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 (1×8) 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. Resistive switching of oxygen plasma treated GaSe is showing a promising ION/IOFF ratio (104–106). Multiple highly stable logic gate operations are demonstrated in a single device based on gate and optical inputs. Most attractive feature of the devices is the re‐configurability that can switch between two logic gates by just adjusting the gate voltages, e.g., NAND/NOR and AND/NAND, OR/NOR, AND/NAND.