AlGaN-based UV-B laser diode with a high optical confinement factor
Shunya Tanaka, Yuya Ogino, Kazuki Yamada, Tomoya Omori, Reo Ogura, Shohei Teramura, Moe Shimokawa, Sayaka Ishizuka, Ayumu Yabutani, Sho Iwayama, Kosuke Sato, Hideto Miyake, Motoaki Iwaya, Tetsuya Takeuchi, Satoshi Kamiyama, Isamu Akasaki
Abstract
To reduce the threshold current density (Jth) of ultraviolet (UV)-B AlGaN-based laser diodes, we investigated the critical parameters aiming to increase the injection efficiency ηi and the optical confinement factor Γ. Optimization of the thickness of the waveguide layer, the average Al content of the p-type AlGaN cladding layer, and the film thickness of the cladding layer demonstrated that the device characteristics can be improved. This optimization achieved a reduction in Jth to 13.3 kA cm−2 at a lasing wavelength of 300 nm, thus offering the lowest Jth value yet achieved for a UV-B laser diode.