Solution-processed, hybrid 2D/3D MoS₂/Si heterostructures with superior junction characteristics

Abstract

We report a theoretical and experimental investigation of the hybrid heterostructure interfaces between atomically thin MoS₂ nanocrystals (NCs) on Si platform for their potential applications towards next-generation electrical and optical devices. Mie theory-based numerical analysis and COMSOL simulations based on the finite element method have been utilized to study the optical absorption characteristics and light-matter interactions in variable-sized MoS₂ NCs. The size-dependent absorption characteristics and the enhancement of electric field of the heterojunction in the UV-visible spectral range agree well with the experimental results. A lithography-free, wafer-scale, 2D material on a 3D substrate hybrid vertical heterostructure has been fabricated using colloidal n-MoS₂ NCs on p-Si. The fabricated p-n heterojunction exhibited excellent junction characteristics with a high rectification ratio suitable for voltage clipper and rectifier applications. The current-voltage characteristics of the devices under illumination have been performed in the temperature range of 10-300 K. The device exhibits a high photo-to-dark current ratio of ∼3 × 10³ and a responsivity comparable to a commercial Si photodetector. The excellent heterojunction characteristics demonstrate the great potential of MoS₂ NC-based hybrid electronic and optoelectronic devices in the near future.