Abstract
AlGaN deep-ultraviolet (DUV) laser diodes (LDs) have the potential to be used as compact, highly
efficient, high-power light sources. The applications for DUV-LDs include sterilization and fine
machining of metals or other advanced materials, utilizing the advantage of the very high absorption
coefficient of UV light in these materials. In this work, we fabricated AlGaN DUV LD structures based
on growth techniques used for fabricating highly efficient AlGaN light-emitting diodes (LEDs). We
fabricated laser mirror facets using a laser stealth-dicing (SD) process. With current injection of 0.1 KA/
cm2 and under continuous wave (CW) operation, spontaneous emission at a wavelength of 277 nm from
the DUV LD structure with a relatively high external quantum efficiency (EQE) of over 4% was
observed. We also observed stimulated emission by optical pumping from the AlGaN DUV quantum
wells with low threshold exciting power density of 68 kW/cm2 at room temperature.
