Electrically injected GaN-on-Si blue microdisk laser diodes.

III-nitride blue microdisk laser diodes are highly desirable in emerging applications, such as augmented reality, virtual reality, and visible light communication. However, the electrically pumped blue microdisk lasers have been lagging for decades owing to weak optical confinement and large internal absorption loss. In this study, the waveguide layers and cladding layers were carefully engineered to enhance the optical confinement and reduce internal absorption loss. Therefore, the first electrically injected blue microdisk laser diodes grown on Si substrates have been successfully fabricated, and exhibited a resistor-capacitance-limited bandwidth of 24.1 GHz, showing highly promising applications in high-speed and large-modulation-bandwidth visible light communication.