Resonant-cavity blue light-emitting diodes fabricated by two-step substrate transfer technique

GaN-based blue resonant-cavity light-emitting diodes (RCLEDs) have been fabricated by the two-step substrate transfer technique. The prefabricated structure was separated from its sapphire substrate by laser lift-off (LLO) process and was then transferred to a Si permanent substrate. By optimising the LLO process and adopting an indium tin oxide thin film and two high-reflectivity dielectric distributed Bragg reflectors, a narrow linewidth of 0.3 nm at 461.2 nm, corresponding to a quality factor of approximately 1530, has been observed from a blue RCLED under a current density of 2 kA/cm². It indicates that a high quality optical resonator has been realised by this approach.