Organometallic Vapor Phase Epitaxial Growth and Characterization of Aluminum - Gallium - Indium - Phosphide for Visible Emitters.

The (Al_{rm y} Ga_{rm 1-y}) _{.5}In_ {.5}P materials system lattice matched to GaAs substrates is an attractive material for the realization of high performance visible laser diodes. Room temperature cw operation of double heterostructure (DH) and multiquantum well lasers has been reported, with threshold current densities as low as 1.7 kA/cm^2. A structure with single quantum well active region is expected to reduce lasing thresholds; achievement of such a structure is the primary goal of this work. Organometallic vapor phase epitaxial (OMVPE) growth of the ternaries Ga_{rm x} In_{rm 1-x}P and Al_{rm x}In _{rm 1-x}P is examined to determine optimum growth conditions and lattice match. Epilayers are characterized using Raman spectroscopy, electroreflectance, photoluminescence, and surface morphology comparisons. Lattice -matched Ga_{.5}In _{.5}P/GaAs superlattices are used to study the arsenide/phosphide interface. Quantum shifts in the luminescence from a series of Al_ {.5}In_{.5}P/Ga _{.5}In_ {.5}P superlattices is observed. Growth of Al_{rm x}Ga _{rm 1-x}P is also examined, and found to require very high growth temperature. Lattice matched (Al_{rm x}Ga_{rm 1-x} )_{.5}In _{.5}P layers are grown and studied using photoluminescence and Raman spectroscopy. The Raman spectrum shows a three-mode behavior, with InP-like, GaP -like, and AlP-like modes. The direct bandgap is found to vary linearly with composition. Tellurium (n-type) and zinc(p-type) doping is accomplished for material with x = 0.6, for use as laser cladding layers. Finally, double heterostructure (DH) and graded -index separate confinement heterostructure (GRIN-SCH) laser diodes are prepared from these materials. In each case, the cladding layers are composed of (Al_ {.6}Ga_{.4}) _{.5}In_ {.5}P, and the structure is grown on a zinc-doped GaAs substrate. For the DH, Ga_ {.5}In_{.5}P active regions of thickness 1000 A and 1500 A are tried. In the GRIN-SCH, the graded-index regions are formed by compositionally graded layers of (Al_{rm x} Ga_{rm 1-x}) _{.5}In_ {.5}P (0.2 <=q x <=q 0.6), and the active gain region consists of a 100 A Ga_{.5}In _{.5}P quantum well. The GRIN-SCH results in a reduced threshold current compared to the DH, with broad area threshold current densities approaching 1.0 kA/cm^2.