Planar disorder- and native-oxide-defined photopumped AlAs-GaAs superlattice minidisk lasers

Data are presented on the photopumped laser operation of planar AlAs-GaAs superlattice (SL) minidisk lasers. The SL minidisk (70 Angstrom AlAs, 30 Angstrom GaAs; 100 periods; similar to 37 mu m diameter) is defined by impurity-induced layer disordering (IILD), followed by wet oxidation (N-2+H2O vapor, 400 degrees C which surrounds the minidisk with a low-refractive-index AlGaAs oxide. The planar minidisks exhibit laser operation at lambda-7540 Angstrom, with wider mode separation (Delta lambda-13 Angstrom) than disks defined by only IILD (a smaller refractive index step) and cleaved sample edges. The mode separation of Delta lambda similar to 13 Angstrom corresponds to disk modes that utilize 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.