Embedded porous-InP reflectors for 1550 nm resonant-cavity light-emitting diodes with narrowband emission

InGaAsP-based short-wavelength infrared (SWIR) resonant-cavity light-emitting diodes (RC-LEDs) were fabricated with a homoepitaxial porous-InP distributed Bragg reflectors (DBRs). The 20-pair n-InP/undoped-InP stack structure had been transformed into the porous-InP/undoped-InP DBR structure with a 94.7% reflectivity at 1550 nm through an electrochemical etching process. The resonant cavity formed between the porous DBR and the air/epilayer interface amplifies specific wavelengths. An effective cavity length of approximately 7.5λ, including DBR penetration depth, was obtained from the longitudinal mode spacing. Compared with the non-DBR LED, the RC-LED shows 41% higher electroluminescence intensity and a linewidth reduced from 160 to 27 nm at 40 mA, indicating improved optical confinement and a resonance cavity effect. The InP-based RC-LED structure with embedded porous-InP DBR structures has potential applications to SWIR light source for short-to-mid-reach optical interconnects.