2D material-based plasmonic phototransistors under strong optical excitations

Periodic arrays of metallic structures are commonly placed on top of two-dimensional (2D) materials to enhance the local electric field and light absorption, particularly for light detection and generation. However, such enhancement often leads to substantial increases in local temperature under high-power optical excitations. This study explores the feasibility of devising a novel phototransistor with moderate field enhancement yet superior thermal management. Our approach involves strategically placing metal nanoparticles beneath the 2D material and atop silicon pillars. Heat is efficiently transferred to the substrate, mitigating thermal accumulation by leveraging the high thermal conductivity of both metals and silicon. Through multi-physics numerical modeling, our analysis reveals that the proposed design has higher quantum efficiency under high-power excitations than plain and plasmonic phototransistors decorated with metal nanoparticles atop.