Strong exciton-photon coupling in hybrid InGaN-based microcavities on GaN substrates

Abstract

A 5λ-thick hybrid semiconductor/dielectric GaN-based microcavity grown by metal-organic chemical vapor deposition on a c-plane bulk GaN substrate was investigated using angle-resolved photoluminescence and angle-resolved cathodoluminescence techniques at room and low temperature (5.8 K), respectively. The cavity structure consisted of an InGaN multiple quantum well active region emitting at 400 nm and sandwiched between 29.5 pair bottom semiconductor AlN/GaN and 13.5 pair top dielectric SiO2/SiNx distributed Bragg reflectors. The cavity supported strong exciton-photon coupling with a record 75 meV vacuum Rabi splitting energy at 5.8 K. The measured room temperature Rabi splitting energy of 45 meV is still close to the highest Rabi splitting energies reported in literature confirming that the strong coupling regime still persists at room temperature.