Over 50% carrier injection efficiency in AlGaN-based UV-B laser diodes enabled by combining Al-content-drop design and low-temperature epitaxy
Abstract
We demonstrate a significant improvement in carrier injection efficiency (ηi) in AlGaN-based UV-B laser diodes (LDs) through a combined approach of the Al-content-drop design and low-temperature epitaxy, both introduced to preserve the electron-blocking barrier and suppress Al–Ga interdiffusion at heterointerfaces. Four devices fabricated with different quantum well AlN molar fractions (0.23–0.35) showed lasing at 297–319 nm with ηi ranging from 42% to 52%, representing a more than threefold improvement over previously reported polarization-doped UV LDs. A peak optical power of 570 mW and a wall-plug efficiency of 2.9% were achieved under pulsed operation (50 ns, 0.01% duty). These results experimentally verify that maintaining a large conduction-band offset and abrupt interfaces, rather than wavelength-dependent factors, overwhelmingly governs ηi improvement in polarization-doped UV-B LDs. Our findings establish a practical design and growth guideline for highly efficient current-injection UV-B LDs.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (15)
Takumu Saito
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Rintaro Miyake
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Shundai Maruyama
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Yusuke Sasaki
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Shogo Karino
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Ryota Watanabe
Yuma Miyamoto
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Tomoya Tanikawa
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Rintaro Kobayashi
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Sho Iwayama
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Hideto Miyake
Koichi Naniwae
Ushio, Inc 3 ., Gotenba 412-0038,
Satoshi Kamiyama
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Tetsuya Takeuchi
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,
Motoaki Iwaya
Department of Materials Science and Engineering, Meijo University 1 , Nagoya 468-8502,