Abstract
The photoluminescence spectra of InAs quantum dots (QDs) embedded into four types of In x Ga 1-x As/GaAs (x = 0.10, 0.15, 0.20 and 0.25) multi quantum well MBE structures have been investigated at 300 K in dependence on the QD position on the wafer. PL mapping was performed with 325 nm HeCd laser (35 mW) focused down to 200 μm (110 W/cm 2 ) as the excitation source. The structures with x = 0.15 In/Ga composition in the In x Ga 1-x As capping layer exhibited the maximum photoluminescence intensity. Strong inhomogeneity of the PL intensity is observed by mapping samples with the In/Ga composition of x ≥ 0.20-0.25. The reduction of the PL intensity is accompanied by a gradual "blue" shift of the luminescence maximum at 300 K as follows from the quantum dot PL mapping. The mechanism of this effect has been analyzed. PL peak shifts versus capping layer composition are discussed as well.
Original language | English |
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Pages (from-to) | 5542-5545 |
Number of pages | 4 |
Journal | Applied Surface Science |
Volume | 252 |
Issue number | 15 |
DOIs | |
State | Published - 30 May 2006 |
Keywords
- InAs quantum dots
- PL scanning spectroscopy