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:
Apr. 16, 2002
Filed:
Sep. 14, 1999
Yasuhiko Akaike, Kawasaki, JP;
Shoichi Washizuka, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An evaluating method capable of quickly measuring the essential lifetime in an epitaxial wafer for a light emitting device independently from the excited carrier density without breaking the epitaxial wafer is configured to obtain the non-radiative lifetime from the changing rate of intensity of luminescence light generated by irradiating exited light onto the epitaxial wafer at the time when the changes with time becomes below a given value, and to obtain the non-radiative lifetime independent from the excited carrier density. An epitaxial wafer for a light emitting device with a higher emission efficiency than conventional ones has a non-radiative lifetime not shorter than 20 nanoseconds obtained by the evaluating method, and the diffusion amount of zinc into its active layer does not exceed 1E13 atoms per cm .