Miniband transport quantum well detector

A two-color semiconductor miniband transport quantum well detector, comprising:

• a substrate;
• first means, disposed on the substrate, for absorbing photons of a first wavelength band, the first absorbing means comprising a multilayer structure including a first plurality of quantum well layers interleaved with superlattice barrier layers, the layers having predetermined thicknesses and compositions;
• first and second contact layers disposed on top and bottom surfaces, respectively, of the first multilayer structure;
• second means, disposed on the first contact layer, for absorbing photons of a second wavelength band, the second absorbing means comprising a second multilayer structure including a second plurality of quantum well layers interleaved with superlattice barrier layers, the layers having predetermined thicknesses and compositions;
• and
• a third contact layer disposed on the second multilayer structure distal from the first multilayer structure;
• wherein each quantum well layer has a bound ground energy state and a bound excited energy state, each superlattice barrier layer has a miniband of energy states in resonance with the excited energy states of its adjacent quantum well layers, the minibands and excited energy states provide an electrically continuous channel across the layers of each respective multilayer structure for carriers excited by absorption of photons when different electric potentials are applied to the contact layers, and the minibands are at least approximately fifty meV wide.

A broad-band semiconductor miniband-transport quantum well detector, comprising:

• a substrate;
• means, disposed on the substrate, for absorbing incident photons, the absorbing means comprising a multilayer structure including
• a first plurality of first quantum well layers, each first layer having a bound ground energy state and a bound excited energy state,
• a second plurality of second quantum well layers, each second layer having a bound ground energy state and a bound excited energy state,
• a third plurality of third quantum well layers, each third layer having a bound ground energy state and a bound excited energy state, and
• a plurality of superlattice barrier layers disposed between proximate ones of the first, second, and third quantum well layers, each superlattice barrier layer having a miniband of energy states in resonance with the excited energy states of its adjacent quantum well layers;
• and
• first and second contact layers disposed on top and bottom surfaces, respectively, of the multilayer structure;
• wherein the minibands and excited energy states provide an electrically continuous channel across the layers for carriers excited from the ground energy states to the excited energy states and minibands by absorption of photons when different electric potentials are applied to the contact layers, the excited energy states of the first quantum well layers are positioned near the bottom of the minibands, the excited energy states of the second quantum well layers are positioned near the middle of the minibands, and the excited energy states of the third quantum well layers are positioned near the top of the minibands.

A semiconductor for detecting electromagnetic radiation, comprising:

• a plurality of doped quantum well layers, each doped quantum well layer comprising a bound ground energy state and one of a plurality of different bound excited energy states;
• a plurality of superlattice barrier layers interleaved with the quantum well layers, each superlattice layer having a miniband of energy states in resonance with the excited energy states of its adjacent quantum well layers and strongly coupled to other minibands, said plurality of bound excited energy states of the quantum well layers being arranged in a predetermined pattern within the minibands of energy states of said superlattice barrier layers;
• whereby carriers excited from the ground states to the excited energy states and miniband states by absorption of photons of electromagnetic radiation are transported for collection when an electric field is applied across the quantum well layers and the superlattice barrier layers, wherein said minibands are at least approximately fifty meV wide;
• and
• wherein said predetermined pattern comprises at least a first quantum well's excited energy state positioned near the bottom of the minibands, at least a second quantum well's excited energy state positioned near the middle of the minibands, and at least a third quantum well's excited energy state positioned near the top of the minibands.

A semiconductor miniband-transport quantum well detector, comprising:

• a substrate;
• absorbing means, disposed on the substrate, for absorbing incident photons, the absorbing means comprising a multilayer structure including a plurality of quantum well layers, each quantum well layer having a bound ground energy state and a bound excited energy state responsive to the photons, and a plurality of superlattice barrier layers interleaved between the quantum well layers, each superlattice barrier layer having a miniband of energy states in resonance with the excited energy states of its adjacent quantum well layers;
• first and second contact layers disposed on top and bottom surfaces, respectively, of the multilayer structure;
• and
• wherein the minibands and the excited energy states provide an electrically continuous channel across the layers for carriers excited from the ground energy states and minibands by absorption of photons when different electric potentials are applied to the contact layers, and wherein the excited states are positioned in a predetermined pattern of plural different energy states within the minibands.

A semiconductor miniband-transport quantum well detector, comprising:

• a substrate;
• absorbing means, disposed on the substrate, for absorbing incident photons, the absorbing means comprising a multilayer structure including a plurality of quantum well layers, each quantum well layer having a bound ground energy state and a bound excited energy state responsive to the photons, and a plurality of superlattice barrier layers interleaved between the quantum well layers, each superlattice barrier layer having a miniband of energy states in resonance with the excited energy states of its adjacent quantum well layers;
• first and second contact layers disposed on top and bottom surfaces, respectively, of the multilayer structure;
• and
• wherein the minibands and the excited energy states provide an electrically continuous channel across the layers for carriers excited from the ground energy states and minibands by absorption of photons when different electric potentials are applied to the contact layers, and wherein the excited states are positioned in a predetermined pattern of plural different energy states within the minibands, wherein the predetermined pattern comprises excited energy states positioned near the bottom, middle, and top of the minibands.