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:
May. 16, 1995
Filed:
Feb. 25, 1993
Takamasa Suzuki, Nagoya, JP;
Hiroshi Ito, Toyohashi, JP;
Nippondenso Co., Ltd., Kariya, JP;
Abstract
An object of the invention to vary a light absorption coefficient within wider limits in a light absorption control semiconductor device. The device includes at least three quantum wells Q1, Q2, Q3. The width of the respective quantum wells and barriers is set such that wave functions of electrons in the respective quantum wells interact in a resonance state where the quantized energy levels in either one of conduction and valence bands are matched. In addition, the width and material of the respective quantum wells are set so that one of the bands is brought into the resonance state where the quantized energy levels at the respective quantum wells are matched in a state where no electric field is applied or a state where a suitable electric field is applied in a direction perpendicular to the junctions. The light absorption is changed by controlling components of the electric field perpendicular to the junctions. Since only one band is brought into the resonance state, the light absorption coefficient can be made greater.