Internal efficiency analysis of 280-nm light emitting diodes

Compact ultraviolet light sources are currently of high interest for a range of applications, including solid-state lighting, short-range communication, and bio-chemical detection. We report on the design and analysis of AlGaN-based light-emitting diodes with an emission wavelength near 280 nm. Internal device physics is investigated by three-dimensional numerical simulation. The simulation incorporates a drift-diffusion model for the carrier transport, built-in polarization, the wurtzite energy band-structure of strained quantum wells, as well as radiative and nonradiative carrier recombination. Critical material parameters are identified and their impact on the simulation results is investigated. Limitations of the internal quantum efficiency by electron leakage and nonradiative recombination are analyzed. Increasing the stopper layer bandgap is predicted to improve the quantum efficiency and the light output of our LED substantially.