are even smaller, only a few MHz, which are far away from the requirement of fast and large data wireless transmission for VLC. [5] To enhance the data transmission rates, complex modulation schemes and/ or equalization have to be utilized, which, however, hinder the further developments and applications. In addition, Si-based optoelectronic devices, like Si PDs, a bluefiltering technology are still used currently for shorter wavelength visible light detection, which suffers from complexity and low light transmittance. Furthermore, considering the development and mature application of GaN-based devices, there is a trend to realize the multifunctional single chip integration. However, the relative low coupling efficiency in the GaNbased optoelectronic devices still cannot meet the requirements. In this case, it is important to develop novel GaN-based optoelectronic devices with superior performances as alternative for miniaturization, simplification, and integration. To solve these problems, the concept of incorporating GaN-based devices with exotic optical resonances has been proposed. [5] Surface plasmons (SPs), microcavities, such as whispering gallery modes (WGMs) and distributed Bragg reflectors (DBR) are common optical resonant structures to improve the performances of GaN-based devices. [6][7][8][9] SPs are intrinsic electromagnetic modes excited at the metal-dielectric interfaces, accompanied with the collective oscillation behaviors of free electrons on the metal-side surfaces. [10] Giant electric field enhancement generates at the interface with exponentially decay along the perpendicular direction. Inside the GaN-based devices, the excitation of SPs can greatly enhance the density of states of the electron-hole pairs and improve the competitiveness of the radiative recombination to the non-radiative recombination. [11] It has also been demonstrated tremendously in early works that using SPs enables a path to break the optical diffraction limit of the semiconductor lasers and boost the light-matter coupling intensities in subwavelength dimensions. [11][12][13][14][15][16][17] In addition, GaN-based microcavities, such as photonics crystals, DBR, and micro disks, can confine and manipulate light. [18][19][20] By matching one or more dimensions of the cavities to the wavelength of the confined light, exotic effects can be produced, such as enhanced luminescence, directional emission, low-threshold lasing, etc. When light illuminates microcavities, the confined electron-hole pairs interact with the cavity photons. Their interaction rate relative to the average Being direct wide bandgap, III-nitride (III-N) semiconductors have many applications in optoelectronics, including light-emitting diodes, lasers, detectors, photocatalysis, etc. Incorporation of III-N semiconductors with high-efficiency optical resonances including surface plasmons, distributed Bragg reflectors and micro cavities, has attracted considerable interests for upgrading their performance, which can not only reveal the new coupling mechanism...