p-Graphene/Quantum Dot/n-GaAs Mixed-Dimensional Heterostructure Junction for Ultrathin Light-Emitting-Diodes

Abstract

2D materials such as graphene hold significant potential for optoelectronic applications due to their unique surface properties and strong light-matter interaction. Despite the promise, achieving high-performance photonic devices using 2D materials alone remains challenging, and therefore, integrating 2D materials with different dimensional semiconductors has emerged as an alternative approach to enhance device functionality. Here, p-type graphene/InAs quantum dot (QD)/n-type GaAs mixed-dimensional heterojunctions are demonstrated for 1.3 mu m light-emitting diodes (LEDs) by using the p-graphene as an ultrathin hole injection layer. These ultrathin hybrid devices show 800 x stronger electroluminescence output powers than the reference LEDs without p-graphene. Energy band alignments at the heterojunction interface are also investigated by measuring UV photoemission spectroscopy to elucidate electrical characteristics. The novel hybrid 2D p-graphene/0D QD/n-GaAs light-emitting diodes open up new ways for efficient ultrathin nanoscale light-emitting optoelectronic devices.