The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 10, 1989
Filed:
Jun. 08, 1987
Darryl D Coon, Pittsburgh, PA (US);
Runkiri P Karunasiri, Sherman Oaks, CA (US);
Hui C Liu, Pittsburgh, PA (US);
University of Pittsburgh of the Commonwealth System of Higher Education, Pittsburgh, PA (US);
Abstract
A fast, real time method and apparatus for long wavelength infrared photodetection employs a quantum well from which stored electrons are ejected by photoemission and replaced by electrons which tunnel through a barrier bounding one side of the quantum well. The photodetector comprises a semiconductor device having a quantum well layer separated from an emitter layer on one side by a first barrier layer and from a collector layer on the other side by a second barrier layer. The first barrier is higher than the second which in turn is higher than the Fermi level in the quantum well layer. Photons excite electrons in the quantum well to an excited state from which they flow over the second barrier to the collector layer. Electrons tunnel from the emitter through the first barrier to the quantum well at the rate at which they are depleted by photoemission so that the detector is suitable for use with high pulse rate digital communication signals.