Asahi Kasei and a research group led by Professor Hiroshi Amano of the Center for Integrated Research of Future Electronics, Institute of Materials and Systems for Sustainability, Nagoya University, have developed a deep-ultraviolet (in wavelength span of UV-C) semiconductor laser using aluminum nitride (AlN) substrate. The result is the world's shortest lasing wavelength at 271.8 nm under pulsed current injection at room temperature.

The successfully developed short-wavelength UV-C semiconductor laser uses a 2-inch AlN substrate manufactured by Crystal IS, Inc., an Asahi Kasei Group company. Featuring an extremely low defect density of 10³/cm², the 2-inch AlN substrate of Crystal IS made a major contribution to the successful short-wavelength lasing.

Whereas previous short-wavelength semiconductor lasers were only achieved down to 336 nm, the current result is the world's first in the UV-C range of 200-280 nm. It is expected that UV-C semiconductor lasers would be used not only in healthcare such as topical disinfection and therapeutic applications, but also expand to applications including measurement and analysis of DNA and particulates, and gas analysis.

Lasing under current injection in the ultraviolet range was considered challenging because of the extremely high resistance of the material. Key factors in this successful development were 1) employing a specially designed p-side layer to simultaneously realize sufficient light confinement and reduced device resistance, 2) suppressing light scattering loss by using AlN substrate with few defects, and 3) combining Asahi Kasei's leading thin-film crystal growth technology with the outstanding process technology and evaluation technology of Nagoya University's CIRFE Transformative Electronics Facilities (C-TEFs). This research result thus holds the key to high-output UV-C solid-state light sources which have long been sought.

Asahi Kasei and Nagoya University will advance joint research toward the achievement of continuous room-temperature lasing to enable the commercialization of UV-C semiconductor laser products.

The successful research result has been reported in the online version of Applied Physics Express on October 30, 2019, as below.

Title

A 271.8 nm deep-ultraviolet laser diode for room temperature operation

Authors

Ziyi Zhang, Maki Kushimoto, Tadayoshi Sakai, Naoharu Sugiyama, Leo J. Schowalter, Chiaki Sasaoka and Hiroshi Amano

DOI

https://doi.org/10.7567/1882-0786/ab50e0

Corporate Profile of Crystal IS, Inc.

Establishment

1997 (spinoff from Rensselaer Polytechnic Institute)

Location

New York, USA

CEO

Larry Felton

Operations

Development, manufacturing and sale of UVC LEDs using AlN substrates

Website

http://www.cisuvc.com/

Cross-sectional structure and emission characteristics of the UVC semiconductor laser element