Highly stacked quantum-dot laser fabricated using a strain compensation technique

Abstract

We used a strain compensation technique to fabricate highly stacked InAs quantum-dot (QD) structures on InP(311)B substrates. We stacked 60 layers of InAs QDs without degrading the crystal quality and produced a structure with a total QD density of $4.73\times {10}^{12}∕{\mathrm{cm}}^2$ . We then fabricated a broad area laser diode with a 30-layer stack of InAs QDs using conventional photolithography. The laser diode showed ground state lasing at $1.58\mu \mathrm{m}$ with a threshold current of $162\mathrm{mA}$ . The achievement of ground state lasing is due to the increase in QD density, which is a result of using the strain compensation technique.