Photon detector system
AssigneeBattelle Development Corporation
InventorPhilip A. Ekstrom
Life of this patent
Estimating the term…
Abstract
A photon detector includes a semiconductor device, such as a Schottky barrier diode, which has an avalanche breakdown characteristic. The diode is cooled to cryogenic temperatures to eliminate thermally generated charge carriers from the device. The diode is then biased to a voltage level exceeding the avalanche breakdown threshold level such that, upon receipt of a photon, avalanche breakdown occurs. This breakdown is detected by appropriate circuitry which thereafter reduces the diode bias potential to a level below the avalanche breakdown threshold level to terminate the avalanche condition. Subsequently, the bias potential is reapplied to the diode in preparation for detection of a subsequently received photon.
Claims17
A photon detection system capable of providing an electrical output signal upon receipt of a single photon, comprising:
- a semiconductor device including a pair of electrical leads connected thereto, said device exhibiting avalanche breakdown when one or more free charge carriers are present therein and an electrical potential in excess of a predetermined avalanche potential is placed across said pair of electrical leads,
- biasing means for applying an electrical potential across said pair of electrical leads in excess of said predetermined avalanche potential,
- cooling means for cryogenic cooling of said semiconductor device such that thermally generated charge carriers within said device are substantially eliminated, whereby avalanche breakdown occurs as a result of free charge carriers produced by photon absorption by said semiconductor device, and
- means for sensing avalanche breakdown of said semiconductor device and for producing said electrical output signal in response thereto.
A method of detecting receipt of a photon, comprising the steps of:
- positioning a semiconductor device for receipt of a photon, said device exhibiting avalanche breakdown when one or more free charge carriers are present in said device and an electrical potential in excess of a predetermined avalanche potential is placed across said device,
- biasing said device electrically with a bias potential which exceeds said predetermined avalanche potential of said device, while at the same time cooling said device sufficiently to eliminate substantially all thermally generated electrical charge carriers in said device,
- detecting avalanche breakdown of said device upon receipt of a photon thereby,
- quenching said avalanche breakdown by reducing said bias potential below said predetermined avalanche potential, and
- increasing said bias potential to a level exceeding said predetermined avalanche potential after said avalanche breakdown has been quenched, whereby a subsequently received photon may be detected.
A detector array for detecting receipt of photons striking said array, comprising:
- means defining a plurality of photon sensitive Schottky barrier devices arranged in an array,
- means for cooling said Schottky barrier devices sufficiently to eliminate substantially all of the free thermally generated charge carriers in said devices,
- voltage biasing means for reverse biasing electrically each of said Schottky barrier devices to a potential sufficient to cause a self-sustaining avalanche current flow in each such device in the presence of a charge carrier produced by photon absorption in the device, and
- means for detecting avalanche current flow through each of said Schottky barrier devices in said array, with detection of avalanche current flow through a device indicating receipt of a photon by said device.
A sensor for providing an electrical indication upon receipt of a photon having a wavelength in the infrared region, comprising:
- a semiconductor device including a pair of electrical leads, said device exhibiting avalanche current flow in which the presence of a single free charge carrier in the material making up said device produces a substantial number of charge carriers in said conduction band when an electrical potential in excess of an avalanche potential level is supplied to said leads, whereby a self-sustaining current flow between said leads is initiated, and
- means for cooling said semiconductor device to a cryogenic temperature at which substantially all of the thermally generated charge carriers are removed from said conduction band, whereby a photon striking said device elevates a charge carrier to said conduction band, producing avalanche current flow.
Dependencies are inferred from the claim text.