Red-green-blue (RGB) full-color micro light-emitting diodes (μ-LEDs) fabricated from semipolar (20-21) wafers, with a quantum-dot photoresist color-conversion layer, were demonstrated. We also demonstrated high-stability quantum dot-converted 3-in-1 full-color minilight-emitting diodes passivated with low-temperature atomic layer deposition. A hybrid QD-NR-μLED with an ALD passivation layer and efficient NRET has been fabricated to produce a monolithic RGB μLED device with QDs printed by super-inkjet (SIJ) printing system. We also presented a high-efficiency InGaN red micro-LED fabricated by the incorporation of superlattice structure, atomic layer deposition passivation, and a distributed Bragg reflector. Finally, a high 3-dB bandwidth semipolar (20-21) long-wavelength InGaN/GaN μLED has been demonstrated.