Two-dimensional reconfigurable electronics enabled by asymmetric floating gate

Reconfigurable devices with customized functionalities hold great potential in addressing the scaling limits of silicon-based field-effect transistors (FETs). The conventional reconfigurable FETs are limited to the applications in logic circuits, and the commonly used multi-gate programming strategies often lead to high power consumption and device complexity. Here, we report a reconfigurable WSe2 optoelectronic device that can function as photodiode, artificial synapse, and 2-bit memory in a single device, enabled by an asymmetric floating gate (AFG) that can continuously program the device into different homojunction modes. The lateral p–n homojunction formed in the AFG device exhibits high-performance self-powered photodetection, with a responsivity over 0.17 A·W−1 and a wide detection spectral range from violet to near-infrared region. The AFG device can also mimic synaptic features of biological synapses and achieve distinct potentiation/depression behaviors under the modulation of both drain-source bias and light illumination. Moreover, when working as a 2-bit memory via the transition between n–n+ and p–n homojunctions, the AFG device shows four distinct conductive states with a high on/off current ratio over 106 and good repeatability. Combining reduced processing complexity and reconfigurable functionalities, the WSe2 AFG devices demonstrate great potential towards high-performance photoelectric interconnected circuits.