Georgia Tech Research Corporation

Polaroid Corporation

Kevin F Brennan

Thomas K Gaylord

Elias N Glytsis

William D Hunt

Christopher J Summers

Joe N Haralson

The present disclosure relates to an avalanche photodiode having edge breakdown suppression. The photodiode comprises a p contact and an n contact, as well as a plurality of device layers disposed between the p contact and the n contact. The device layers include, in order from the p contact to the n contact, a primary well, a decoupler layer, a multiplication layer, a charge sheet, an absorption layer, and a substrate. The layers are constructed so as to have particular volumes of charge which affects the order in which they deplete. With the preferred order of depletion, the multiplication layer will deplete before the decoupler layer and the decoupler layer will deplete before the charge sheet when a negative bias is applied to the avalanche photodiode. This results in a joint opening effect within the avalanche photodiode which effectively suppresses edge breakdown.

Avalanche photodiode having edge breakdown suppression

The present invention is directed to a combined SAW sensor and a SPR sensor for evaluating an analyte, as well as a novel method for evaluating an analyte by utilizing a surface acoustic wave (SAW) sensor to determine the mass of the analyte and utilizing a surface plasmon resonance (SPR) sensor to determine the permittivity of the analyte. In accordance with one aspect of the invention, an apparatus is provided for evaluating an analyte. In one embodiment, the apparatus includes a piezoelectric substrate, a SAW sensor disposed on the substrate, and a SPR sensor disposed on the substrate in close proximity to the SAW sensor. In another embodiment, the apparatus more broadly includes a SAW sensor and a SPR sensor coupled to the surface acoustic wave sensor. In a preferred embodiment, the apparatus the SAW sensor includes two interdigital transducers and a chemically sensitive film interposed between the two interdigital transducers. The apparatus further includes an acousto-optic tunable filter (AOTF) disposed on the substrate, and interposed between the SAW sensor and the SPR sensor. The AOTF functions to couple the SAW sensor and the SPR sensor. The SPR sensor includes a chemically sensitive film, and an acoustic absorber is disposed on the substrate and interposed between the AOTF and the chemically sensitive film of the SPR sensor. Finally, an optical fiber may be configured to introduce a broadband light into the substrate, the optical fiber disposed to direct the light through the AOTF, the acoustic absorber, and the chemically sensitive film of the SPR sensor.

Method and apparatus for evaluating an analyte

An Acoustic Charge Transport Imager, suitable for use as a High Definition Television (HDTV) camera element, is disclosed in which an array of amorphous hydrogenated silicon based avalanche photodiodes are combined with acoustic charge transport channels in a GaAs substrate, to achieve very high speed read out of photogenerated charge. High speed read out allows the fabrication of detector arrays large enough to meet the resolution requirements of HDTV while ensuring operation within the timing constraints of the HDTV frame rate.

Acoustic charge transport imager

Continuously tunable, biased, semiconductor superlattice electron interference filter/emitter which can serve, for example, as a hot electron emitter in a ballistic transistor, provides energy selectivity for substantially ballistic electron wave propagation at electron energies above the superlattice potential barriers. The layers of the biased superlattice have alternatively high and low electron refractive indices wherein each layer is a quarter or half of an electron wavelength in thickness and wherein the quantum well barrier widths are adjusted in the direction of emission to provide the desired energy selectivity.

Semiconductor biased superlattice tunable interference filter/emitter

Solid state quantum mechanical electron and hole wave devices

Semiconductor, quantum well, electron and hole slab waveguides include a substrate semiconductor layer, a film semiconductor layer, and a cover semiconductor layer, wherein the semiconductor layers provide substantially ballistic transport for electrons and wherein the thicknesses and compositions of the semiconductor layers are determined in accordance with the inventive method to provide a waveguide.

Semiconductor quantum well electron and hole waveguides

A low noise doped quantum well avalanche photodector (APD) having repeated superlattice units. Where the majority carriers are electrons, each unit is formed from p.sup.+ -n.sup.+ layers of a first material having a first ionization threshold, a near intrinsic layer of a second material having a smaller ionization threshold, and a near intrinsic layer of the first material. Such an APD can be fabricated in the GaAs/AlGaAs material system.

Growing community of inventors

Atlanta, GA, United States of America

Kevin F Brennan