Abstract
The strong influences of temperature and vacuum on the optical properties of In0.3Ga0.7As surface quantum dots (SQDs) are systematically investigated by photoluminescence (PL) measurements. For comparison, optical properties of buried quantum dots (BQDs) are also measured. The line-width, peak wavelength, and lifetime of SQDs are significantly different from the BQDs with the temperature and vacuum varied. The differences in PL response when temperature varies are attributed to carrier transfer from the SQDs to the surface trap states. The obvious distinctions in PL response when vacuum varies are attributed to the SQDs intrinsic surface trap states inhibited by the water molecules. This research provides necessary information for device application of SQDs as surface-sensitivity sensors.
Highlights
Quantum dots (QDs) have attracted plenty of attentions owing to their valuable properties and potential in developing the new generation of optoelectronic devices [1,2,3], such as solar cells [4,5,6], QD lasers [7, 8], semiconductor optical amplifiers [9], and light-emitting diodes [10]
The sample temperature was immediately reduced to 350 °C after the surface QDs (SQDs) formation, and the sample was unloaded from the molecular beam epitaxy (MBE) growth chamber
The optical properties of In0.3Ga0.7As SQDs and buried quantum dots (BQDs) are comparatively studied by PL and time-resolved PL (TRPL) measurements when the temperature and vacuum vary
Summary
Quantum dots (QDs) have attracted plenty of attentions owing to their valuable properties and potential in developing the new generation of optoelectronic devices [1,2,3], such as solar cells [4,5,6], QD lasers [7, 8], semiconductor optical amplifiers [9], and light-emitting diodes [10]. As one type of quantum dots, colloidal QDs are widely studied as fluorescent indicators and gas sensors, there are still great challenges in integrated systems and on-chip system. Self-assembled surface QDs (SQDs) have innate advantages in integrated systems and on-chip system, due to the fact that they are grown directly on a the III-V semiconductor surface, such as GaAs and InP. The most remarkable characteristic of a sensor design based on SQDs is the fact that the extra light source and detector are not necessary. All these components can be made on one single III-V semiconductor materials chip.
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