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US 7,459,719 B2Granted
Superlattice optical semiconductor device where each barrier layer has high content of group III elements in center portion and low content near well layer
AssigneePanasonic Corporation
InventorsJun Shimizu, Tetsuzo Ueda, Toshikazu Onishi
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Abstract
An optical semiconductor device includes an active layer having a quantum well structure including alternately stacked well layers and barrier layers with a larger band gap than the well layers. The band gap of each of the well layers and the barrier layers is constant, each well layer is uniformly provided with compression strain and each barrier layer is provided with large extension strain in a center portion thereof along the thickness direction and small extension strain in portions thereof in the vicinity of the well layers.
Claims8
An optical semiconductor device comprising:
- an active layer having a quantum well structure including alternately stacked well layers and barrier layers, wherein a bandgap of said barrier layers is larger than a bandgap of said well layers,
- wherein each of said well layers and said barrier layers has a constant band gap,
- said active layer is made of a group III-V compound semiconductor,
- wherein a content of each of group III elements and group V elements is uniform in each of said well layers regardless of a position therein,
- wherein a content of each of group III elements and group V elements is varied along the thickness direction in each of said barrier layers,
- each of said well layers is made of AlGaInAs and each of said barrier layers is made of AlGaAsP,
- wherein contents of said AlGaAsP are modulated in each of said barrier layers,
- Ga and P contents in each of said barrier layers are increased in a center portion thereof in the thickness direction and reduced in a portion thereof in the vicinity of said well layer.
5 more elements
Dependencies are inferred from the claim text.