Construction and Multifunctional Photonic Applications of Light Absorption-Enhanced Silicon-Based Schottky Coupled Structures

Abstract

To expand the detection capabilities of silicon (Si)-based photodetector and address key scientific challenges such as low light absorption efficiency and short carrier lifetime in Si-based graphene photodetector. This work introduces a novel Si-based Schottky coupled structure by in situ growth of 3D-graphene and molybdenum disulfide quantum dots (MoS₂ QDs) on Si substrates using chemical vapor deposition (CVD) and plasma-enhanced chemical vapor deposition (PECVD) techniques. The findings validate the “dual-enhanced absorption” effect, enhancing the understanding of the mechanisms that improve optoelectronic performance. The synergistic effect of 3D-graphene's natural nano-resonant cavity and MoS₂ QDs enhances light absorption efficiency and extends carrier lifetime. Introducing MoS₂ QDs broadens and intensifies the built-in electric field, promoting the separation of photogenerated electrons and holes. The photodetector exhibits a wideband light response in the wavelength range of 380–2200 nm. It stably outputs photocurrent under high-frequency (1 kHz) modulated laser (2200 nm), with a responsivity (R) of 40 mA W⁻¹ and detectivity (D^*) of 1.15 × 10⁹ Jones. Photodetectors show the ability to process and encrypt complex binary signals and achieve versatility in “AND” gate and “OR” gate logic operations, as well as image sensing (240 × 200 pixels).