An asymmetric Schottky black phosphorus transistor for enhanced broadband photodetection and neuromorphic synaptic functionality

Artificial synapses that mimic the functions of biological neurons are fundamental elements of brain-like computing. The development of artificial synaptic devices is essential for future applications in computer vision information processing capabilities, as well as in the fields of artificial intelligence and the internet of things. However, the sensitivity and detection range of optoelectronic synapses, which can also serve as self-powered photodetectors, pose urgent challenges to be addressed, particularly in achieving broadband and infrared detection using individual two-dimensional semiconductor materials. In this report, a black phosphorus (BP)-based transistor is constructed based on the potential difference between BP nanoflake and Au electrodes with varying thicknesses. The BP-based transistor demonstrates the capability for self-powered photodetection across a wide range from 405 to 1064 nm. Furthermore, with the assistance of an external voltage of 1 V, the photodetection bandwidth of the BP-based transistor extends to 2200 nm. The specific detectivity and responsivity of the BP-based transistor are high to 2.47 × 1011 and 1.94 × 1011 Jones, 34 and 20 A/W under 1550 and 2200 nm infrared light, respectively. Moreover, the BP-based transistor can emulate the “learning-forgetting” behaviors of optoelectronic synapses under light with a wide range from 405 to 2200 nm, providing an effective approach for brain-like recognition processing systems. This research contributes to the advancement of optoelectronic synaptic devices and holds promise for future developments in neuromorphic computing.