Enhanced Carrier Dynamics and Excitation of Optically Stimulated Artificial Synapse Using van der Waals Passivation Layers

Abstract

Advances in the semiconductor industry have been limited owing to the constraints imposed by silicon-based CMOS technology; hence, innovative device design approaches are necessary. This study focuses on "more than Moore" approaches, specifically in neuromorphic computing. Although MoS2 devices have attracted attention as neuromorphic computing candidates, their performances have been limited due to environment-induced perturbations to carrier dynamics and the formation of defect states. This study explores the integration of hydrocarbon (HC) layers onto active MoS2 channels to enhance neuromorphic computing characteristics. HC layers were employed in the proposed MoS2 field-effect transistor to facilitate stable optoelectrical control over the MoS2 channel under high-power stimulation. The improved electrical performance, stability, and synaptic behaviors of the HC-capped MoS2 devices compared to uncapped counterparts were experimentally demonstrated. The combination of optical and electrical tuning allowed for in-sensor computing applications that mimic human sensory behaviors. The impact of HC passivation on device performance was evaluated, and its potential for applications in neuromorphic computing with high stability was demonstrated across wide-ranging environmental conditions. The unique capabilities of HC-capped MoS2 devices were demonstrated by examining the spike duration-dependent plasticity and spiking timing-dependent plasticity. Thus, the proposed approach offers a promising avenue for advancing neuromorphic computing technologies.