We report the current progress of our development of near-ultraviolet (NUV) III-nitride vertical-cavity LED emitters and avalanche photodetectors grown by metalorganic chemical vapor deposition (MOCVD). The III-N emitters are designed to be UV vertical-cavity surface-emitting lasers operating at 369.5nm. We describe the development of the growth and processing of an air-gap/AlGaN distributed Bragg reflector (DBR) consisting of five-pairs of quarter-wavelength layers of Al<sub>0.12</sub>Ga<sub>0.88</sub>N and air-gap regions created by selective chemical etching. A 4-6λ cavity was employed in the laser structure. We also report on the electrical and optical emission characteristics of these microcavity emitters. The photodetectors are GaN- and AlGaN-based p-i-n avalanche photodiodes (APDs) designed for front-side illumination. We report on the electrical and optical detection characteristics of these photodetectors.
Optically pumped VCSELs with a 1λ thick optical cavity lasing at 375 nm have been demonstrated using a pulsed 248 nm KrF excimer laser source. To realize a high-reflectivity mirror on the bottom of the cavity, five-period airgap/ Al0.05Ga0.95N DBRs with a large refractive index contrast have been employed while the top mirror was formed by dielectric DBRs consisting of twelve pairs HfO2/SiO2. The lowest threshold incident power density measured at room temperature was estimated to be ~270 kW/cm2. The achieved optically pumped VCSEL demonstrates the possibility that the airgap/AlxGa1-xN DBRs can be used as a mirror for injection laser devices.