An optically controlled synaptic device based on a PdSe ₂ /α-In ₂ Se ₃ vdW heterostructure FET

-based counterparts. Logic gate operations (OR and AND) were demonstrated using 642 nm, 785 nm and 406 nm wavelengths as optical inputs. In addition, a three-layer artificial neural network (ANN) was trained to recognize a 28 × 28 pixel handwritten MNIST dataset by a backpropagation algorithm demonstrating high recognition accuracy of 96% and 97% under wavelengths of 642 nm and 406 nm, respectively. This study provides an effective strategy for the development of versatile optically controlled neuromorphic devices as fundamental building blocks for on-chip optical communication, optoelectronic logic, and Internet of Things (IoT) applications.