Low-threshold-current (~85 mA) of AlGaN-based UV-B laser diode with refractive-index waveguide structure
Shunya Tanaka, Yuya Ogino, Kazuki Yamada, Reo Ogura, Shohei Teramura, Moe Shimokawa, Sayaka Ishizuka, Sho Iwayama, Kosuke Sato, Hideto Miyake, Motoaki Iwaya, Tetsuya Takeuchi, Satoshi Kamiyama
Abstract
We report on a refractive-index waveguide AlGaN-based ultraviolet-B band (UV-B) laser diode grown on a sapphire substrate, which achieves a laser oscillation at a low threshold current (Ith), ∼85 mA. The refractive index waveguide structure in a ridge-type structure is fabricated by a unique method combining dry inductively coupled plasma reactive ion etching and wet etching with tetramethylammonium hydroxide solution. Using this structure, the longitudinal-mode transverse optical confinement is successfully achieved, in which the ridge width is 3 μm, demonstrating a low Ith of UV-B laser diode.