Photodetecting device
AssigneeFujitsu Limited
InventorsPrafulla Masalkar, Hiroji Ebe
Life of this patent
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Abstract
A first multi-quantum well structure 12 is formed on a GaAs substrate 10. The first multi-quantum well structure 12 is formed of an AlGaAs barrier layer and a GaAs well layer alternately laid one on the other to form a multi-quantum well. The GaAs barrier layer is not doped with an impurity. A second multi-quantum well structure 14 is formed on the first multi-quantum well structure 12. The second multi-quantum well structure 14 is formed of an AlGaAs barrier layer and a GaAs well layer alternately laid one on the other to form a multi-quantum well. The GaAs barrier layer is not doped with an impurity. Whereby a required electrode area can be smaller to thereby obtain higher detection sensitivity.
Claims5
A photodetecting device comprising:
- a first quantum dot structure including a first quantum dot doped with an impurity, and having a first quantum level absorbing a radiation of a first wavelength;
- and
- a second quantum dot structure laid on the first quantum dot structure, including a second quantum dot non-doped with an impurity, and having a second quantum level absorbing a radiation of a second wavelength which is different from the first wavelength.
A photodetecting apparatus comprising:
- a photodetecting device comprising:
- a first quantum well structure including a first quantum well layer doped with an impurity, and having a first quantum level absorbing a radiation of a first wavelength;
- and
- a second quantum well structure laid on the first quantum well structure, including a second quantum well layer non-doped with an impurity, and having a second quantum level absorbing a radiation of a second wavelength which is different from the first wavelength;
- and
- a radiation source for radiating a pump radiation for generating a carrier in the second quantum-well layer in order to absorb the radiation of the second wavelength by the second quantum level.
A photodetecting apparatus comprising:
- a photodetecting device comprising:
- a first quantum well structure including a first quantum well layer non-doped with an impurity, and having a first quantum level absorbing a radiation of a first wavelength;
- and
- a second quantum well structure laid on the first quantum well structure, including a second quantum well layer non-doped with an impurity, and having a second quantum level absorbing a radiation of a second wavelength which is different from the first wavelength;
- a first radiation source for radiating a first pump radiation for generating a carrier in the first quantum well layer in order to absorb the radiation of the first wavelength by the first quantum level;
- and
- a second radiation source for radiating a second pump radiation for generating a carrier in the second quantum well layer in order to absorb the radiation of the second wavelength by the second quantum level.
A photodetecting apparatus comprising:
- a photodetecting device comprising:
- a first quantum dot structure including a first quantum dot non-doped with an impurity, and having a first quantum level absorbing a radiation of a first wavelength;
- and
- a second quantum dot structure laid on the first quantum dot structure, including a second quantum dot non-doped with an impurity, and having a second quantum level absorbing a radiation of a second wavelength which is different from the first wavelength;
- a first radiation source for radiating a first pump radiation for generating a carrier in the first quantum dot in order to absorb the radiation of the first wavelength by the first quantum level;
- and
- a second radiation source for radiating a second pump radiation for generating a carrier in the second quantum dot in order to absorb the radiation of the second wavelength by the second quantum level.
Dependencies are inferred from the claim text.