Semiconductor light emitting device
AssigneeKabushiki Kaisha Toshiba
InventorsYukie Nishikawa, Shinji Nunotani
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Abstract
A semiconductor light emitting device includes an active layer, an electrode formed above the active layer, a current spreading layer formed between the active layer and the electrode, having n-type conductivity, having a larger bandgap energy than the active layer, and spreading electrons injected from the electrode in the plane of the active layer, and a surface processed layer formed on the current spreading layer, having a larger bandgap energy than the active layer, and having an uneven surface region with a large number of concave-convex structures. The electrode is not formed on the uneven surface region. The conduction band edge energy from the Fermi level of the surface processed layer is higher than that of the current spreading layer.
Claims20
A semiconductor light emitting device comprising:
- an active layer;
- an electrode formed above the active layer;
- a current spreading layer formed between the active layer and the electrode, having n-type conductivity, having a larger bandgap energy than the active layer, and spreading electrons injected from the electrode in the plane of the active layer;
- and
- a surface processed layer formed on the current spreading layer, having a larger bandgap energy than the active layer, and having an uneven surface region with a large number of concave-convex structures,
- wherein the electrode is not formed on the uneven surface region, and
- wherein the conduction band edge energy from the Fermi level of the surface processed layer is higher than that of the current spreading layer.
A semiconductor light emitting device comprising:
- an active layer;
- an electrode formed above the active layer;
- a current spreading layer formed between the active layer and the electrode, having p-type conductivity, having a larger bandgap energy than the active layer, and spreading holes injected from the electrode in the plane of the active layer;
- and
- a surface processed layer formed on the current spreading layer, having a larger bandgap energy than the active layer, and having an uneven surface region with a large number of concave-convex structures,
- wherein the electrode is not formed on the uneven surface region, and
- wherein the conduction band edge energy from the Fermi level of the surface processed layer is higher than that of the current spreading layer.
A semiconductor light emitting device comprising:
- an active layer;
- a current spreading layer formed above the active layer, having a larger bandgap energy than the active layer, and spreading injected carriers in the plane of the active layer;
- an intermediate layer formed on the current spreading layer, having a larger bandgap energy than the active layer, and having a lower Al composition than the current spreading layer;
- a surface processed layer formed on the intermediate layer, and having an uneven surface region in which a large number of concave-convex structures are formed at its surface;
- and
- an electrode formed on a region except the uneven surface region of the surface processed layer, and injecting the carriers to operate,
- wherein the surface processed layer having a higher conduction band edge energy from the Fermi level than that of the intermediate layer, or
- wherein the surface processed layer having a higher valence band edge energy from the Fermi level than that of the intermediate layer.
Dependencies are inferred from the claim text.