GaN-based blue laser diodes

Autor: Takao Miyajima, Kenji Funato, Takeharu Asano, Shiro Uchida, Toshimasa Kobayashi, Satoru Kijima, Katsunori Yanashima, Tomonori Hino, Motonobu Takeya, Tsuyoshi Tojyo, Masao Ikeda, Tsunenori Asatsuma, Shigetaka Tomiya
Rok vydání: 2001
Předmět:
Zdroj: Journal of Physics: Condensed Matter. 13:7099-7114
ISSN: 1361-648X
0953-8984
Popis: We report our recent progress on GaN-based high-power laser diodes (LDs), which will be applied as a light source in high-density optical storage systems. We have developed raised-pressure metal-organic chemical vapour deposition (RP-MOCVD), which can reduce the threading-dislocation density in the GaN layer to several times 108 cm-2, and demonstrated continuous-wave (cw) operation of GaN-based LD grown by RP-MOCVD. Furthermore, we found that the epitaxial lateral overgrowth (ELO) technique is useful for further reducing threading-dislocation density to 106 cm-2 and reducing the roughness of the cleaved facet. By using this growth technique and optimizing device parameters, the lifetime of LDs was improved to more than 1000 hours under 30 mW cw operation at 60 °C. Our results proved that reducing both threading-dislocation density and consumption power is a valid approach to realizing a practical GaN-based LD. On the other hand, the practical GaN-based LD was obtained when threading-dislocation density in ELO-GaN was only reduced to 106 cm-2, which is a relatively small reduction as compared with threading-dislocation density in GaAs- and InP-based LDs. We believe that the multiplication of non-radiative centres is very slow in GaN-based LDs, possibly due to the innate character of the GaN-based semiconductor itself.
Databáze: OpenAIRE