Mid and deep ultraviolet (UV) laser diodes remain among the least explored devices in semiconductor optoelectronics, despite their importance for spectroscopy, biochemical sensing, disinfection, and emerging quantum photonics. Here, we demonstrate an electrically pumped AlGaN-based laser diode operating in the UV-B band (280-315 nm). The device is grown by molecular beam epitaxy (MBE) on single-crystal AlN substrate and fabricated in a ridge-waveguide geometry. The laser diode operates at 298.5 nm and exhibits a relatively low threshold current density of 3.4 kA/cm2. Clear nonlinear light-current characteristics and pronounced spectral narrowing with a full-width-at-half-maximum (FWHM) of 0.2 nm are measured above threshold.
@article{arxiv.2601.19201,
title = {Electrically pumped AlGaN edge-emitting UV-B laser diodes grown by molecular beam epitaxy},
author = {Huabin Yu and Shubham Mondal and Rui Shen and Md Tanvir Hasan and David He and Jiangnan Liu and Samuel Yang and Minming He and Omar Alkhazragi and Danhao Wang and Mackillo Kira and Parag Deotare and Di Liang and Zetian Mi},
journal= {arXiv preprint arXiv:2601.19201},
year = {2026}
}