Vertical-Cavity Surface-Emitting Lasers Based on Submonolayer InGaAs Quantum Dots

Abstract

Molecular beam epitaxy-grown 0.98-mum vertical-cavity surface-emitting lasers (VCSELs) with a three-stack submonolayer (SML) InGaAs quantum-dot (QD) active region and fully doped Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> As-GaAs DBRs was studied. Large-aperture VCSELs demonstrated internal optical losses less than 0.1% per one pass. Single-mode operation throughout the whole current range was observed for SML QD VCSELs with the tapered oxide apertures diameter less than 2 mum. Devices with 3-mum tapered-aperture showed high single-mode output power of 4 mW and external quantum efficiency of 68% at room temperature