Marked reduction in photocarrier lifetime by erbium doping into self-assembled InAs quantum dots embedded in strain-relaxed InGaAs barriers

GaAs/AlAs Multilayer Cavity with Er-Doped InAs Quantum Dots Embedded in Strain-Relaxed InGaAs Barriers for Ultrafast All-Optical Switches

“…In this study, a higher In composition (x) of 0.45, which was estimated by the high-resolution X-ray diffraction (HRXRD) of the Er-doped QD sample, was used in the strain-relaxed InGaAs barrier to reduce the height of the potential barrier. The In compositon of the Er-doped QD sample indicated in the previous report 17) was also estimated to be 0.32 by HRXRD.…”

“…The detailed growth conditions and procedures have already been described in ref. 17. In this study, a higher In composition (x) of 0.45, which was estimated by the high-resolution X-ray diffraction (HRXRD) of the Er-doped QD sample, was used in the strain-relaxed InGaAs barrier to reduce the height of the potential barrier.…”

“…Recently, we have found that the decay time can be further shortened by erbium doping during the molecular beam epitaxy (MBE) of the InAs QDs with strain-relaxed InGaAs barriers. 17) In this study, we investigated the nonlinear optical properties of the Er-doped InAs QDs embedded in strainrelaxed InGaAs barriers. We improved the optical nonlinear signal from the 20-layer stack of QDs by increasing the In composition in the strain-relaxed InGaAs barriers.…”

GaAs/AlAs Multilayer Cavity with Er-Doped InAs Quantum Dots Embedded in Thin Strain-Relaxed In0.45Ga0.55As Barriers for Ultrafast All-Optical Switches

“…Furthermore, the decay time can be further shortened ($3 ps) by Er-doping during the growth of the InAs QDs with strain-relaxed In 0:35 Ga 0:65 As barriers. 20) Recently, we have grown a GaA/AlAs multilayer cavity with Er-doped InAs QDs embedded in a high In concentration strain-relaxed In 0:45 Ga 0:55 As barrier for ultrafast alloptical switches. 21) In this structure with a high refractive index =2 cavity layer, the optical field is enhanced at the sides of the cavity layer.…”

GaAs/AlAs multilayer cavity with Er-doped InAs quantum dots embedded in extremely thin strain-relaxed InGaAs barriers for ultrafast all-optical switches

“…Another characteristic feature of the QDs is the fast decay (~ 18 ps) of the photo-generated carriers into the nonradiative centers arising from the crystal defects related to the lattice strain relaxation [4], which is useful for the reduction of the pulse pattern effect under high-bit-rate operation. Furthermore, the decay time can be further shortened (~ 3 ps) by Er-doping during the molecular beam epitaxy (MBE) of the InAs QDs with strain-relaxed InGaAs barriers [5]. Recently, we have grown the GaAs/AlAs multilayer cavity with the Er-doped InAs QDs embedded in the strain-relaxed InGaAs barriers for the ultrafast all optical switches [6].…”