Atomically thin synapse networks on van der waals photo-memtransistors

This study reports on a novel architecture of atomically thin synaptic networks constructed on van der Waals (vdW) heterostructures, featuring ultrasmall cells approximately 2 nm thick. Each cell is composed of a trilayer WS₂ semiconductor, functioning as a gate-tunable photoactive synapse known as a photo-memtransistor. Exposure to UV pulse trains allows the WS₂ memristor to generate dopants with atomic precision through direct light-lattice interactions. These, combined with the gate tunability, result in precise modulation of channel conductance, facilitating the potentiation and depression of synaptic cells. The synaptic dynamics observed can be described by a parallel atomistic resistor network model. Furthermore, this device scheme is applicable to other 2D vdW semiconductors, including MoS₂, MoSe₂, MoTe₂, and WSe₂. The integration of these atomically thin photo-memtransistor arrays, where synaptic weights can be controlled via atomistic defect density, suggests potential applications in developing novel artificial neural networks suitable for parallel matrix computations with exceptionally high integration densities.