Design of AlGaN-based lasers with a buried tunnel junction for sub-300 nm emission

This paper discusses the design of electrically-pumped AlGaN-based in-plane lasers emitting at ∼290 nm. Our laser design utilizes strained Al_0.5Ga_0.5N quantum wells, and a novel polarization engineered AlGaN/InGaN/AlGaN-based tunnel junction. The low resistive tunnel junction is used as an intracavity contact in the device in place of the resistive p-type contact; which leads to improved hole injection and a reduced threshold voltage. Hence, room-temperature continuous-wave laser operation could be enabled. Strategies to improve the performance of the tunnel junction contact through the incorporation of low concentrations of boron in the highly-doped AlGaN tunnel junction layers as a means to increase the polarization sheet charge are also discussed. (paper)