Configurable anti-ambipolar photoresponses for optoelectronic multi-valued logic gates

Anti-ambipolar transistors (AATs) are the leading platform for the paradigm shift from binary to multi-valued logic (MVL) circuits, increasing circuit integration density and data processing capacity. However, most AATs with p-n heterojunctions present limited controllability of the transconductance peak, which is key to MVL operation. Here, we report optically configurable AAT/bi-AAT photoresponses implemented with an InSe field-effect transistor for potential MVL operations. The charge trapping and detrapping processes incorporated with manually introduced trap states form the AAT peaks. Furthermore, leveraging a symmetric device configuration, the dark current is significantly suppressed, and AAT photoresponses are highlighted. Contributed by two pathways of trap states, the AAT/bi-AAT photoresponses are switchable by incident optical wavelength. This dependence facilitates optical wavelength to be one of the logic inputs for MVL, based on which we propose circuit-free ternary logic gates in a single device that can achieve more than ∼ 6 and ∼ 19 times improved data density (1 bit per transistor) for NMAX and XNOR, compared with such circuits in a traditional binary design. This work realizes optically controlled AAT photoresponses, paving the way to exploit optical wavelength as a new degree of freedom in MVL computing, offering a route toward ultra-high-density, ultra-low-power, and optically programmable optoelectronic integrated circuits.