Repeatedly and Superbroad Wavelength Tuning Microcavity in a Single Sn-Doped CdS Microcone

It is a challenge to realize the mode wavelength tunability of microcavity in a wide spectral range but critically important for the practical application of optoelectronic devices. Here, we report a Sn-doped CdS microcone with tunable microcavity properties, and the tuning range is more than 300 nm, which is the largest tunable range in a single nanostructure. Its photoluminescence (PL) mapping showed the existence of the periodic structure in the Sn-doped CdS microcone and the selection propagation of longitudinal photons. Cross-sectional radius-dependent PL spectra show a continuous transition from a multimode to three-mode microcavity with decreasing cross-section radius, which indicates the character of different whisper-gallery mode (WGM) microcavity. Meanwhile, the calculation shows that the plane-wave model allows a good description of the detected spectral profile. Our approach simultaneously achieves both wide-spectra and repeatably adjustable microcavity in a single nanostructure. This nanostructure provides a new platform to study wavelength controllability-related high-performance photoelectric detection.