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:
Nov. 13, 2012
Filed:
Mar. 13, 2009
Koichiro Ueno, Tokyo, JP;
Naohiro Kuze, Tokyo, JP;
Koichiro Ueno, Tokyo, JP;
Naohiro Kuze, Tokyo, JP;
Asahi Kasei Microdevices Corporation, Tokyo, JP;
Abstract
Provided is an infrared light emitting device in which dark current and diffusion current caused by thermally excited holes are suppressed. Thermally excited carriers (holes) generated in a first n-type compound semiconductor layer () tend to diffuse in the direction of a π layer (). But, the dark current by holes is reduced by providing an n-type wide band gap layer () with a larger band gap than the first layer () and the π layer () that suppresses the hole diffusion between the first layer () and the π layer (). The wide band gap layer () has a band gap shifted relatively to valence band direction by n-type doping and thereby more effectively functions as a diffusion barrier for the thermally excited holes. Namely, the band gap and n-type doping of the wide band gap layer () are adjusted to suppress diffusion of the thermally excited carriers.