選択成長マイクロファセットを用いたGaN系面発光型レーザー

Abstract

GaN microfacets have been grown by selective-area metalorganic vapor phase epitaxy (SA-MOVPE) and applied to GaN-based surface-emitting lasers. The crystal orientation of the microfacets was strictly controlled by the shapes of the mask-openings and growth conditions so that vertical and inclined microfacets were obtained. Hexagonal microprisms (HMPs) of GaN with 5-50μm in diameters have extremely smooth vertical side walls of GaN {10 1 0} microfacets. These GaN HMPs lase by optical pumping and have the inscribed hexagonal optical paths. Additionally, GaN-based horizontal cavity surface-emitting lasers (HCSELs) were successfully fabricated. The GaN-based HCSELs have Fabry-Perot cavity and outer micromirrors, which consist of SA-MOVPE grown {11 2 0} vertical and {11 2 2} inclined microfacets, and lased at room temperature by pulsed current injection. The laser beam emitted laterally from a Fabry-Perot cavity {11 2 0} vertical micromirror is reflected by a {11 2 2} inclined outer micromirror so as to be directed upward. The GaN-based HCSEL has a current-confining structure because the incorporation probability of p-type dopants (Mg) is strongly influenced by facet orientation (growth direction).