| 摘要 |
PROBLEM TO BE SOLVED: To provide a nitride semiconductor laser having a photonic crystal structure as a diffraction grating, which presents suitableΓ<SB>well</SB>andΓ<SB>pc</SB>and reduces internal stress within AlGaN. SOLUTION: A secondary diffraction grating layer 17 comprises a secondary photonic crystal structure 21, and is provided between a first conductive type clad layer 13 and a second conductive type clad region 15. An active layer 19 is provided between the first conductive type clad region 13 and the secondary diffraction grating layer 17. The first conductive type clad region 13 includes at least first and second AlGaN layers 25 and 27. The first AlGaN layer 25 is provided between the second AlGaN layer 27 and the active layer 19, and the first AlGaN layer 25 is closest to the active layer 19 in the first conductive type clad layer 13. The Al composition of the first AlGaN layer 25 is largest in the first conductive type clad region 13, and the Al composition of the second AlGaN layer 27 is smaller than the Al composition of the first AlGaN layer 25. COPYRIGHT: (C)2008,JPO&INPIT
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