Optical semiconductor device
View Patent ↗According to one embodiment, an optical semiconductor device includes an n-type semiconductor layer, a p-type semiconductor layer, and a functional part. The functional part is provided between the n-type semiconductor layer and the p-type semiconductor layers. The functional part includes a plurality of active layers stacked in a direction from the n-type semiconductor layer toward the p-type semiconductor layer. At least two of the active layers include a multilayer stacked body, an n-side barrier layer, a well layer and a p-side barrier layer. The multilayer stacked body includes a plurality of thick film layers and a plurality of thin film layers alternately stacked in the direction. The n-side barrier layer is provided between the multilayer stacked body and the p-type layer. The well layer is provided between the n-side barrier layer and the p-type layer. The p-side barrier layer is provided between the well layer and the p-type layer.
1. An optical semiconductor device, comprising:
an n-type semiconductor layer;
a p-type semiconductor layer; and
a functional part provided between the n-type semiconductor layer and the p-type semiconductor layer,
the functional part including a plurality of active layers stacked in a direction from the n-type semiconductor layer toward the p-type semiconductor layer, and
each of at least two of the active layers including:
a multilayer stacked body including a plurality of thick film layers and a plurality of thin film layers alternately stacked in the direction, a thickness of the thin film layers being not more than a thickness of the thick film layers,
an n-side barrier layer provided between the multilayer stacked body and the p-type semiconductor layer,
a well layer; and
a p-side barrier layer provided between the well layer and the p-type semiconductor layer,
wherein the well layer is provided between the n-side barrier layer and the p-side barrier layer.
2. The device according to claim 1 , wherein a thickness of the n-side barrier layer and a thickness of the p-side barrier layer are thicker than 3 nanometers.
3. The device according to claim 1 , wherein a peak wavelength of light emitted from the functional part is longer than 410 nanometers.
4. The device according to claim 1 , wherein the well layer includes In x Ga 1-x N (0.12≦x≦1).
5. The device according to claim 1 , wherein a thickness of the thick film layers is thinner than a thickness of the n-side barrier layer and a thickness of the p-side barrier layer.
6. The device according to claim 1 , wherein the n-side barrier layer and the p-side barrier layer include GaN.
7. The device according to claim 1 , wherein a thickness of the n-side barrier layer and a thickness of the p-side barrier layer are thinner than 10 nanometers.
8. The device according to claim 1 , wherein the n-type semiconductor layer, the p-type semiconductor layer and the functional part include a nitride semiconductor.
9. The device according to claim 1 , wherein a concentration of In contained in the well layer is higher than a concentration of In contained in the n-side barrier layer and the p-side barrier layer.
10. The device according to claim 1 , wherein a thickness of the thick film layers is not less than 1.0 nanometer and not more than 3 nanometers, and a thickness of the thin film layers is less than 1.5 nanometers.
11. The device according to claim 1 , wherein the thick film layers include GaN, the thin film layers include InGaN.
12. The device according to claim 1 , wherein a number of the active layers is more than 4.
13. The device according to claim 1 , wherein each of the active layers includes the multilayer stacked body, the n-side barrier layer, the well layer and the p-side barrier layer.
14. The device according to claim 1 , wherein a number of the thin film layers is more than 4.
15. The device according to claim 1 , wherein a fluorescence image obtained by observing light emitted from the functional part in the direction have anisotropic patterns of light intensity.
16. The device according to claim 1 , wherein a peak wavelength of light emitted from the functional part is not less than 410 nanometers and less than 500 nanometers, and a number of the active layers is more than 4.
17. The device according to claim 1 , wherein a peak wavelength of light emitted from the functional part is not less than 500 nanometers and not more than 650 nanometers, and a number of the active layers is not less than 3 and not more than 10.
18. The device according to claim 1 , wherein in one of the active layers,
the n-side barrier layer contacts the multilayer stacked body,
the well layer contacts the n-side barrier layer, and
the p-side barrier layer contacts the well layer.
19. The device according to claim 1 , wherein a bandgap energy in a bulk structure having a composition of the thin film layers is smaller than a bandgap energy in a bulk structure having a composition of the thick film layers.
20. The device according to claim 1 , wherein a band gap energy of the well layer is smaller than a bandgap energy of the n-side barrier layer, and is smaller than a bandgap energy of the p-side barrier layer.