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

✍ Scribed by Takahiro Kitada; Tomoya Takahashi; Hyuga Ueyama; Ken Morita; Toshiro Isu

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 302 KB
• Volume: 323
• Category: Article
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2010.10.120

✦ Synopsis

Effects of erbium doping on photocarrier lifetime have been investigated for self-assembled InAs quantum dots (QDs) embedded in strain-relaxed In 0.35 Ga 0.65 As barriers grown on (1 0 0) GaAs substrates by molecular beam epitaxy. Time-resolved transmission change measurements were performed on 20-layer stacks of the Er-doped InAs QDs at room temperature using 0.1 ps laser pulses with the center wavelength of 1:5 mm. Fast and slow decay components were observed in the temporal profile of each Er-doped InAs QD sample. The slow decay component attributed to the radiative recombination process in the QDs was well suppressed by increasing Er-doping density. Moreover, the decay time of the fast component due to the nonradiative process was markedly reduced by the incorporation of Er dopants during the QD formation. A decay time of 3.5 ps was obtained for the Er-doped InAs QD sample with a sheet density of incorporated Er dopants per QD layer of 2:7 Â 10 13 cm À2 .