Current confinement in an optical device using AlAs oxide
Oxidation of AlAs layers embedded in a GaAs/AlGaAs p-i-n device employing a vertical cavity surface emitting laser structure was investigated as a possible scheme for current confinement. Two samples having similar structures, except for a thick AlAs layer embedded on top of the active region for one sample were grown by molecular beam epitaxy. Surface emission spectra of the two oxidized devices taken at room temperature showed a significant increase in total integrated intensity relative to the unoxidized samples. However, the degradation of satellite peaks owing to the reduction of cavity effects in the oxidized sample without thick AlAs layer implies a significant alteration in the quality of the mirrors due to oxidation. The presentation of satellite peaks in the other sample indicates that a thick AlAs layer intended for oxidation could also provide current confinement without significantly changing the cavity effect.