Gradient-composition upper-waveguide and electron-blocking layers for enhanced performance in near-ultraviolet laser diodes

A novel laser diode (LD) structure featuring by a gradually composition-graded upper waveguide layer and an electron blocking layer is presented. Our research indicates that, compared to conventional LDs, this “combined structure” eliminates electron accumulation between the two layers. This not only reduces the laser’s threshold current but also enhances the stimulated emission rate, thereby increasing the output power and slope efficiency. The design increases the optical confinement factor, decreases internal losses, optimizes the optical field distribution within the active region, and significantly improves the optoelectronic efficiency of AlGaN-based near-ultraviolet laser diodes.