Lasing characteristics of GaSb/GaAs self-assembled quantum dots embedded in an InGaAs quantum well

The authors report the optical characteristics of GaSb/GaAs self-assembled quantum dots (QDs) embedded in an InGaAs quantum well (QW). Variations in the In composition of the QW can significantly alter the emission wavelength up to 1.3 mu m and emission efficiency. Lasing operation at room temperature is obtained from a 2-mm-long device containing five stacked GaSb QDs in In0.13Ga0.87As QWs at 1.026 mu m with a threshold current density of 860 A/cm(2). The probable lasing transition involves electrons and holes confined in the QW and QDs, respectively, resulting in a large peak modal gain of 45 cm(-1). A significant blueshift of the electroluminescence peak is observed with increased injection current and suggests a type-II band structure. (c) 2007 American Institute of Physics.