AlGaAs/GaAs surface-light-emitting devices by selective liquid phase epitaxy

Abstract

The purpose of this thesis is to study semiconductor surface-light-emitting (SLE) devices experimentally and theoretically, especially in AlGaAs/GaAs double heterostructure (DH) systems. In recent 4 years, surface-emitting (SE) lasers have been of great concern for potential applications to optical signal processing and high power sources. It is very challenging to realize the SE lasers because of various difficulties in the fabrication processes. Several approaches have been proposed an output performances of each approach have also been improved based on the well-developed technologies for present edge-emitting lasers. However, SE lasers are now under research level and will remain so for at least 3 years. New process technologies for surface emission have been developed by employing the novelty of selective liquid phase epitaxy (LPE), by which AlGaAs/GaAs SE lasers with selectively-grown and selectively-meltback-etched beam deflector are fabricated. AlGaAs/GaAs SE light-emitting-diodes (LED``s) with monolithically-integrated lenses are also made by selective meltback and regrowth techniques. As other applications of selective LPE, one-dimensional, two-dimensional AlGaAs microlenses and lens arrays are also developed for passive optical components. In addition the selectively-buried AlGaAs layers can be used as non-absorbing mirrors for high power lasers and electrical isolations for bistable lasers. 780nm AlGaAs//GaAs selective-epitaxy inner-stripe (SEIS) edge-emitting lasers are proposed, fabricated, and characterized. Basic principles of inner-stripe current-blocking layers, which are widely used in commercial AlGaAs/GaAs visible lasers, are analyzed and their electrical properties for current confinements are also studied under SPICE simulations. Half CW operations at room temperature are achieved and CW operations are expected through the process optimization. In case of SE lasers with meltetched-parabolic beam deflectors, the far-field broadening caused...