In As ∕ Ga As self-assembled quantum-dot lasers grown by metalorganic chemical vapor deposition—Effects of postgrowth annealing on stacked InAs quantum dots

We investigated the effects of postgrowth annealing on stacked $\mathrm{In}\mathrm{As}∕\mathrm{Ga}\mathrm{As}$ quantum dots. The blueshift in emission energy by postgrowth annealing depends on the temperature of postgrowth annealing and the growth conditions of stacked InAs quantum dots, such as a spacer thickness or a stacking number. We can control the peak wavelength of stacked InAs quantum dots by changing the temperature of postgrowth annealing and the growth conditions of stacked InAs quantum dots. We achieved continuous-wave lasing with a threshold current of $16.4\mathrm{mA}$ at the wavelength of $1.245\mu \mathrm{m}$ from five layer vertically aligned InAs quantum dots whose upper cladding layer was grown at $600°\mathrm{C}$ .