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. 26, 1991
Filed:
May. 21, 1990
Dennis G Deppe, Austin, TX (US);
Leonard C Feldman, Berkeley Heights, NJ (US);
Rose F Kopf, Bound Brook, NJ (US);
Erdmann F Schubert, New Providence, NJ (US);
Li Wei Tu, Westfield, NJ (US);
George J Zydzik, Warren County, NJ (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
This invention is a semiconductor vertical cavity surface emitting laser comprising a lasing cavity with an active layer, a bottom (rear) mirror and a top (front) mirror, and a front and rear electrodes for applying excitation current in direction substantially parallel to the direction of optical propagation. In accordance with this invention the front mirror comprises a thin, semitransparent metal layer which also acts as the front electrode. The metal layer is upon a highly doped layer forming a non-alloyed ohmic contact. The metal is selected from Ag and Al and is deposited in thickness ranging from 5 to 55 nm. The VCSEL is a semiconductor device wherein the semiconductor material is a III-V or II-VI compound semiconductor. For a VCSEL with GaAs active layer, the light output from the front metal mirror/electrode side yields a high external differential quantum efficiency as high as 54 percent. This is the highest quantum efficiency obtained in VCSEL structures. Quantum efficiencies on the oder of 10 to 30 percent are typical for prior art VCSEL structures. The VCSEL is suitable for fabrication utilizing planar technology.