InGaN-Based Blue-Violet Laser Diodes Using AlN as the Electrical Insulator

We report on a method for using aluminium nitride (AlN) as the electrical insulator in ridge waveguide blue-violet laser diodes (LDs). The AlN layer is deposited by molecular beam epitaxy, with good sidewall conformality. The slope efficiency (0.66 W/A for uncoated facets) and leakage current (100 pA) of 1.9×700 µm2 devices fabricated using this method are as good as those of conventional LDs with SiO2 insulator. The threshold current is 57 mA compared to 53 mA for SiO2 LDs, accounted for by the higher refractive index of AlN. Self-consistent LD simulations show that a reduction in junction temperature compared to conventional SiO2 LDs is achievable.