Impact of oxygen on band structure at the Ni/GaN interface revealed by hard X-ray photoelectron spectroscopyView Publication
To investigate the impact of oxygen on the band structure at the Ni/p-type GaN interface, the crystal structure and nanoscale impurity distributions were evaluated using transmission electron microscopy and three-dimensional atom probe (3DAP) analysis, respectively. These measurements revealed that the oxygen region existed approximately 5 nm from the GaN surface and that the oxygen concentration was equal to or higher than the Mg acceptor concentration. The band bending and photoelectron spectrum were then simulated using the Mg and oxygen concentration profiles obtained by 3DAP to consider the impact of the interfacial oxygen donors on the photoelectron spectrum measured using hard X-ray photoelectron spectroscopy (HAXPES). The precise band bending was then determined by fitting the simulated spectrum onto the experimental measurements. This showed that the oxygen donors at the interface modulated the band structure and decreased the energy barrier by at least 0.1 eV, which demonstrates the importance of considering the existence of oxygen at the interface. It is, therefore, essential to use techniques like 3DAP and HAXPES to evaluate both the nanoscale impurity distributions and the resulting band structure to fabricate higher-performance devices.
Related PublicationsView All
Highly-efficient operation and mode control in GaN-based VCSELs with a curved mirror
SPIE Photonics West|2023
Tatsushi Hamaguchi, Maiko Ito, Jared A. Kearns, Tomohiro Makino, Kentaro Hayashi, Maho Ohara, Noriko Kobayashi, Tatsuro Jyokawa, Eiji Nakayama, Shouetsu Nagane, Koichi Sato, Yuki Nakamura, Yukio Hoshina, Yuichiro Kikuchi, Takumi Watanabe, Yuya Kanitani, Seiji Kasahara, Yoshihiro Kudo, Susumu Kusanagi, Rintaro Koda, Noriyuki FuutagawaWe report the latest progress of gallium nitride-based Vertical-Cavity Surface-Emitting Lasers (VCSELs) contai […]
Latest progress of high-efficient blue and green VCSELs with curved mirror
Maiko Ito, Tatsushi Hamaguchi, Tomohiro Makino, Kentaro Hayashi, Jared A. Kearns, Maho Ohara, Noriko Kobayashi, Shoetsu Nagane, Koichi Sato, Yuki Nakamura, Yukio Hoshina, Tatsurou Jyoukawa, Takumi Watanabe, Yuichiro Kikuchi, Seiji Kasahara, Susumu Kusanagi, Yuya Kanitani, Eiji Nakayama, Rintaro Koda, Noriyuki FutagawaHighly efficient GaN-VCSELs with curved mirrors were obtained. The peak WPE and output power were 13.4 % and 7 […]