High-efficiency photon–electron coupling resonant emission in GaN-based microdisks on Si**Project supported by the National Key R&D Program of China (Grant Nos. 2016YFB0400102 and 2016YFB0400602), the National Natural Science Foundation of China (Grant Nos. 61674076, 61422401 and 51461135002), the Collaborative Innovation Center of Solid State Lighting and Energy-Saving Electronics, Open Fund of the State Key Laboratory on Integrated Optoelectronics (Grant No.

Abstract

Resonance effects caused by the photon–electron interaction are a focus of attention in semiconductor optoelectronics, as they are able to increase the efficiency of emission. GaN-on-silicon microdisks can provide a perfect cavity structure for such resonance to occur. Here we report GaN-based microdisks with different diameters, based on a standard blue LED wafer on a Si substrate. A confocal photoluminescence spectroscopy is performed to analyze the properties of all microdisks. Then, we systematically study the effects of radial modes and axial modes of these microdisks on photon–electron coupling efficiency by using three-dimensional finite-difference time-domain simulations. For thick microdisks, photon–electron coupling efficiency is found to greatly depend on the distributions of both the radial modes and the axial modes, and the inclined sidewalls make significant influences on the axial mode distributions. These results are important for realization of high-efficiency resonant emission in GaN-based microcavity devices.