AlGaN-based UVC laser diodes operating at wavelengths are expected to be a low-cost, environmentally friendly, and highly efficient laser light source for a variety of applications. In this study, we further reduced the threshold gain by improving the optical confinement and improved the threshold current density while lowering drive voltage. A threshold current density of 2.8 kA/cm2 was achieved in pulsed current operation, and an operating voltage as low as 9.6 V was also achieved. Furthermore, the packaged device successfully emits CW light at a wavelength of 274.8 nm with a DC current operation of over 110 mA at 5°C.
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