PLANAR DISORDER-DEFINED AND NATIVE-OXIDE-DEFINED PHOTOPUMPED ALAS-GAAS SUPERLATTICE MINIDISK LASERS

Data are presented on the photopumped laser operation of planar AlAs-G aAs superlattice (SL) minidisk lasers. The SL minidisk (70 Angstrom Al As, 30 Angstrom GaAs; 100 periods; similar to 37 mu m diameter) is def ined by impurity-induced layer disordering (IILD), followed by wet oxi dation (N-2+H2O vapor, 400 degrees C which surrounds the minidisk with a low-refractive-index AlGaAs oxide. The planar minidisks exhibit las er operation at lambda-7540 Angstrom, with wider mode separation (Delt a lambda-13 Angstrom) than disks defined by only IILD (a smaller refra ctive index step) and cleaved sample edges. The mode separation of Del ta lambda similar to 13 Angstrom corresponds to disk modes that utiliz e the perimeter of the oxide-defined disks. In the fabrication of the SL minidisks, ILLD forms a structural and doping difference beyond the disk perimeter that acts, in effect, as a p-n junction during etching or wet oxidation. Etch profiles are shown demonstrating this behavior . (C) 1996 American Institute of Physics.