InGaN light emitting diodes (LED) structure with an embedded 1/4λ-stack nanoporous-GaN/undopedGaN distributed Bragg reflectors (DBR) structure have been demonstrated. Si-heavily doped GaN epitaxial layers (n + -GaN) in the 12-period n + -GaN/u-GaN stack structure are transformed into low refractive index nanoporous GaN structure through the doping-selective electrochemical wet etching process. The central wavelength of the nanoporous DBR structure was located at 442.3 nm with a 57 nm linewidth and a 97.1% peak reflectivity. The effective cavity length (6.0λ), the effective penetration depth (278 nm) in the nanoporous DBR structure, and InGaN active layer matching to Fabry-Pérot mode order 12 were observed in the far-field photoluminescence radiative spectra. High electroluminescence emission intensity and line-width narrowing effect were measured in the DBR-LED compared with the non-treated LED structure. Non-linear emission intensity and line-width reducing effect, from 11.8 nm to 0.73 nm, were observed by increasing the laser excited power. Resonant cavity effect was observed in the InGaN LED with bottom nanoporous-DBR and top GaN/air interface.Gallium nitride (GaN) materials have considerable in optoelectronic devices such as light-emitting diodes (LEDs), laser diodes (LD) 1 , and vertical cavity surface emitting lasers (VCSEL) 2 . High reflectivity distributed Bragg reflectors (DBR) structure, short cavity thickness 3-5 , high transparence conductive layer, efficient transverse current spreading, small current confinement aperture, and resonant cavity controled in the nitride VCSEL need to be improved. Leonard et al. reported on violet nonpolar III-nitride VCSELs with a tunnel junction intracavity contact 6 and an Al ion implanted aperture 7 . The epitaxial AlGaN/GaN stack 8,9 and AlN/GaN stacks 10,11 structures had been reported for the bottom epitaxial DBRs in GaN-based VCSEL devices. Large lattice mismatch and low refractive index different of the stack structures are the challenges for the epitaxial DBR structures with long epitaxial growth time. The AlInN/GaN DBR structure 12,13 is lattice matched to GaN material, but the growth of AlInN layer remains a challenge in InGaN-based LED structures. To realize the high reflectivity with less pairs of stack structure, the air-gap/GaN DBR structures with large refractive index different had been fabricated through selectively anodized processe 14,15 , and thermal decomposition techniques [16][17][18] . But, the low mechanical strength and the tiny high reflective area remains a challenge for the photonic device fabrication. Plawsky et al. 19 . reported the nanoporous material for the photonics through the evaporation induced self-assembly process and oblique or glancing angle deposition. The resonant cavity effect of III-nitride thin-film flip-chip light-emitting diodes with anatase TiO 2 microsphere array were reported 20 . Nanoporous GaN material has been reported as an effective low refractive index for the DBR structure applications [21][22][23] .In this pa...

An indium gallium nitride (InGaN) light-emitting diode (LED) with an embedded porous GaN reflector and a current confined aperture is presented in this study. Eight pairs of n + -GaN:Si/GaN in stacked structure are transformed into a conductive, porous GaN/GaN reflector through an electrochemical wet-etching process. Porous GaN layers surrounding the mesa region were transformed into insulating GaOx layers in a reflector structure through a lateral photoelectrochemical (PEC) oxidation process. The electroluminescence emission intensity was localized at the central mesa region by forming the insulating GaOx layers in a reflector structure as a current confinement aperture structure. The PEC-LED structure with a porous GaN reflector and a current-confined aperture surrounded by insulating GaOx layers has the potential for nitride-based resonance cavity light source applications.