Tunable quantum well infrared detector
AssigneeCalifornia Institute of Technology
InventorJoseph Maserjian
Life of this patent
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Abstract
A novel infrared detector (20, 20', 20"), is provided, which is characterized by photon-assisted resonant tunneling between adjacent quantum wells (22a, 22b) separated by barrier layers (28) in an intrinsic semiconductor layer (24) formed on an n.sup.+ substrate (26), wherein the resonance is electrically tunable over a wide band of wavelengths in the near to long infrared region. An n.sup.+ contacting layer (34) is formed over the intrinsic layer and the substrate is n.sup.+ doped to provide contact to the quantum wells. The detector permits fabrication of arrays (30) (one-dimensional and two-dimensional) for use in imaging and spectroscopy applications.
Claims18
A tunable quantum well detector for detecting infrared radiation comprising (a) a quantum well structure formed in an intrinsic layer comprising a III-V semiconducting material formed over an n.sup.+ bottom contact layer comprising a III-V semiconductor material, (b) an n.sup.+ top contact layer formed on said intrinsic layer, said quantum well structure comprising at least one and less than three quantum wells confined by barrier layers connecting said at least one quantum well to said contact layers, said barrier layers thin enough to permit photon-assisted tunneling of charge carriers from a first electronic state in one well to a second, excited electronic state in an adjacent well, and (c) means for applying an electric field to both said contact layers for adjusting the respective energy levels of said first and second electronic states to achieve said tunability.
An array of tunable quantum well detectors for detecting infrared radiation, each detector comprising (a) a quantum well structure formed in an intrinsic layer comprising a III-V semiconducting material formed over an n.sup.+ bottom contact layer comprising a III-V semiconductor material, (b) an n.sup.+ top contact layer formed on said intrinsic layer, said quantum well structure comprising at least one and less than three quantum wells confined by barrier layers connecting said at least one quantum well to said contact layers, said barrier layers thin enough to permit photon-assisted tunneling of charge carriers from a first electronic state in one well to a second, excited electronic state in an adjacent well, and (c) means for applying an electric field to both said contact layers for adjusting the respective energy levels of said first and second electronic states to achieve said tunability.
Dependencies are inferred from the claim text.