Nitride semiconductor laser device
A nitride semiconductor laser device has a group III nitride semiconductor multilayer structure. The group III nitride semiconductor multilayer structure includes an n-type semiconductor layer, a p-type semiconductor layer and a light emitting layer held between the n-type semiconductor layer and the p-type semiconductor layer, and the p-type semiconductor layer is formed by successively stacking a p-side guide layer, a p-type electron blocking layer in contact with the p-side guide layer and a p-type cladding layer in contact with the p-type electron blocking layer from the side closer to the light emitting layer. The p-side guide layer is formed by stacking a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al. The p-type cladding layer is made of a group III nitride semiconductor containing Al, and the p-type electron blocking layer is made of a group III nitride semiconductor having a larger Al composition than the p-type cladding layer.
1. A nitride semiconductor laser device having a group III nitride semiconductor multilayer structure, wherein
the group III nitride semiconductor multilayer structure includes an n-type semiconductor layer, a p-type semiconductor layer and a light emitting layer held between the n-type semiconductor layer and the p-type semiconductor layer,
the p-type semiconductor layer has a p-side guide layer, a p-type electron blocking layer in contact with the p-side guide layer and a p-type cladding layer in contact with the p-type electron blocking layer successively stacked from the side closer to the light emitting layer,
the p-type cladding layer is made of a group III nitride semiconductor containing Al,
the p-type electron blocking layer is made of a group III nitride semiconductor having a larger Al composition than that of the p-type cladding layer,
the p-side guide layer includes a superlattice structure having a plurality of pairs of alternately stacked layers, each pair including a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al, and
the p-side guide layer further has a layer made of a group III nitride semiconductor containing no Al between the superlattice structure and the light emitting layer.
2. A nitride semiconductor laser device having a group III nitride semiconductor multilayer structure, wherein
the group III nitride semiconductor multilayer structure includes an n-type semiconductor layer, a p-type semiconductor layer and a light emitting layer held between the n-type semiconductor layer and the p-type semiconductor layer,
the p-type semiconductor layer has a p-side guide layer, a p-type electron blocking layer in contact with the p-side guide layer and a p-type cladding layer in contact with the p-type electron blocking layer successively stacked from the side closer to the light emitting layer,
the p-type cladding layer is made of a group III nitride semiconductor containing Al,
the p-type electron blocking layer is made of a group III nitride semiconductor having a larger Al composition than that of the p-type cladding layer,
the p-side guide layer includes a superlattice structure having a plurality of pairs of alternately stacked layers, each pair including a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al, and
the superlattice structure is made of non-doped group III nitride semiconductors, and
the p-side guide layer further has a layer made of a p-type group III nitride semiconductor containing no Al between the superlattice structure and the light emitting layer.
3. The nitride semiconductor laser device according to claim 1 , wherein
the alternately stacked layers in the p-side guide layer are p-type and a p-type dopant concentration of the p-side guide layer is lower than a p-type dopant concentration of the p-type electron blocking layer.
4. The nitride semiconductor laser device according to claim 1 , wherein
the p-type cladding layer is formed by stacking a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al.
5. The nitride semiconductor laser device according to claim 4 , wherein
the p-type cladding layer includes a superlattice structure having a plurality of pairs of alternately stacked layers, each pair including a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al.
6. The nitride semiconductor laser device according to claim 2 , wherein
the alternately stacked layers in the p-side guide layer are p-type and a p-type dopant concentration of the p-side guide layer is lower than a p-type dopant concentration of the p-type electron blocking layer.
7. The nitride semiconductor laser device according to claim 2 , wherein
the p-type cladding layer is formed by stacking a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al.
8. The nitride semiconductor laser device according to claim 7 , wherein
the p-type cladding layer includes a superlattice structure having a plurality of pairs of alternately stacked layers, each pair including a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al.
9. The nitride semiconductor laser device according to claim 1 , wherein
the layer between the superlattice structure and the light emitting layer includes a p-type GaN layer having a thickness larger than a thickness of the layer made of a group III nitride semiconductor containing no Al included in the superlattice structure.
10. The nitride semiconductor laser device according to claim 9 , wherein
the alternately stacked layers in the p-side guide layer are p-type and a p-type dopant concentration of the p-side guide layer is lower than a p-type dopant concentration of the p-type electron blocking layer.
11. The nitride semiconductor laser device according to claim 9 , wherein
the p-type cladding layer is formed by stacking a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al.
12. The nitride semiconductor laser device according to claim 11 , wherein
the p-type cladding layer includes a superlattice structure having a plurality of pairs of alternately stacked layers, each pair including a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al.
13. The nitride semiconductor laser device according to claim 2 , wherein
the layer between the superlattice structure and the light emitting layer includes a p-type GaN layer having a thickness larger than a thickness of the layer made of a group III nitride semiconductor containing no Al included in the superlattice structure.
14. The nitride semiconductor laser device according to claim 13 , wherein
the alternately stacked layers in the p-side guide layer are p-type and a p-type dopant concentration of the p-side guide layer is lower than a p-type dopant concentration of the p-type electron blocking layer.
15. The nitride semiconductor laser device according to claim 13 , wherein
the p-type cladding layer is formed by stacking a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al.
16. The nitride semiconductor laser device according to claim 15 , wherein
the p-type cladding layer includes a superlattice structure having a plurality of pairs of alternately stacked layers, each pair including a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al.