Purcell-enhanced picosecond emission in semiconducting 4H/6H-SiC monocrystalline nanowire forest microcavity

Silicon carbide (core third-generation wide-bandgap semiconductor) nanowires have superior characteristics and vital engineering potential in microelectric and photonic devices operating in harsh high-temperature and strong-irradiation environments. Herein, the dense monocrystalline forest-like 4H- and 6H-SiC nanowires (intrinsically bound as a single crystal) are fabricated using the top–down peeling method. They exhibit broadband light emissions spanning the red–green–blue spectral region. The naturally formed microcavity encapsulating the SiC nanowires yields discrete and multimodal emission lines; the luminescence lifetimes decrease to the order of picoseconds owing to improved photon density of states in the microcavity by the quantum electrodynamic Purcell effect. The measured Purcell factor of 8.35 agrees well with the theoretical value of 8.6. The low-temperature luminescence and work functions show significant dependence on the nanowire polytype. The luminescence exhibits peculiar staircase-function enhancement when the temperature is elevated to 200 K, owing to suppression of nonradiative transition channels.