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Heterostructure Laser

IP.com Disclosure Number: IPCOM000037574D
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Chang, LL: AUTHOR

Abstract

An injection laser made of a heterostructure having n-type InAs and p-type GaSb as the junction electrodes with a layer of InGaAsSb between the electrodes. Variation of the alloy composition permits light output over a spectral range suitable for fiber communication.

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Heterostructure Laser

An injection laser made of a heterostructure having n-type InAs and p-type GaSb as the junction electrodes with a layer of InGaAsSb between the electrodes. Variation of the alloy composition permits light output over a spectral range suitable for fiber communication.

The figure shows the schematic band diagram with the pertinent parameters. On the left and right are, respectively, InAs (Ecl, Evl, Egl) and GaSb (Ec2, Ev2, Eg2). The InAs is naturally, n-type, and GaSb, p-type, which are desirable. They can also be intentionally doped or modulation-doped. The active region is the undoped middle layer. Materials such as InGaAsSb (Ec, Ev, Eg), InGaAs and GaAsSb are suitable. The fact that this layer and the electrodes share common elements makes the entire structure readily achievable by, for example, molecular beam epitaxy.

In operation, under forward bias, electrons (and holes) from InAs (and GaSb) are injected to the conduction band (and valence band) of the alloy, where they recombine and lasing action takes place. The conditions required for the device to operate properly is that Ec lies in energy within the gap of GaSb (Ev2 < Ec < Ec2), and Ev within the gap of InAs (Ev1 < Ev < Ec1). The first requirement is to facilitate electron injection and confinement, and to prevent hole flow. The second requirement applies in an opposite sense. Although the band-edge alignment of the system is not precisely known, it is expected from the simple anion...