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:
Mar. 18, 2003
Filed:
Nov. 15, 1993
Chan-Shin Wu, Torrance, CA (US);
Cheng P. Wen, Mission Viejo, CA (US);
Raytheon Company, Lexington, MA (US);
Abstract
A radiation detector, particularly suited for the detection of long wavelength infrared radiation, employs a plurality of multiple quantum well (MQW) superlattices in a unitary stack. The superlattices are electrically connected in parallel, and current outputs are obtained from the parallel connection as an indication of the incident radiation. Electrical contact layers are provided on the opposite sides of each superlattice, with adjacent superlattices sharing a common contact layer. The number of quantum well/barrier layer periods per superlattice is preferably reduced to about 20-30 divided by the number of superlattices in the stack, as compared to a single-superlattice detector with about 20-30 periods. This allows a common bias voltage applied to the superlattices to be similarly reduced by a factor approximately equal to the number of superlattices in the stack. The reduction in superlattice thickness and bias voltage yields a higher external quantum efficiency, improved signal-to-noise ratio and lower power consumption. The detector can be implemented either as a single color system with similar superlattices, or as a multi-color system in which each superlattice is tuned to a different radiation waveband.