Abstract
This work reports on an experimental investigation of the influence of vertical stacking of quantum dots, the thickness of GaAs potential barriers, and their isovalent doping with bismuth on the photoluminescence properties of InAs/GaAs heterostructures. The experimental samples were grown by ion-beam deposition. We showed that using three vertically stacked layers of InAs quantum dots separated by thin GaAs barrier layers was accompanied by a red-shift of the photoluminescence peak of InAs/GaAs heterostructures. An increase in the thickness of the GaAs barrier layers was accompanied by a blue shift of the photoluminescence peak. The effect of isovalent Bi doping of the GaAs barrier layers on the structural and optical properties of the InAs/GaAs heterostructures was investigated. It was found that the Bi content up to 4.96 atom % in GaAs decreases the density of InAs quantum dots from 1.53 × 1010 to 0.93 × 1010 cm−2. In addition, the average lateral size of the InAs quantum dots increased from 14 to 20 nm, due to an increase in the surface diffusion of In. It is shown that isovalent doping of GaAs potential barriers by bismuth was accompanied by a red-shift of the photoluminescence peak of InAs quantum dots of 121 meV.
Highlights
The formation of III–V nanoheterostructures with quantum dots (QDs) raises the possibility of developing a new generation of photodetectors in the infrared range [1,2,3]
We study the influence of QD vertical stacking, the thickness of GaAs potential barriers and their doping by bismuth on the structural and photoluminescence properties of InAs/GaAs heterostructures
The photoluminescence properties of vertically stacked QD arrays grown by using molecular beam epitaxy (MBE) are well studied in [24,25]
Summary
The formation of III–V nanoheterostructures with quantum dots (QDs) raises the possibility of developing a new generation of photodetectors in the infrared range [1,2,3]. The significant problems of existing HgCdTe detectors are low yield and high cost in comparison with quantum-well infrared photodetectors (QWIPs) [4]. The QWIPs, in turn, have a simpler technology but a low quantum efficiency and require cooling. One way to solve these problems is to grow semiconductor heterostructures in which QDs are embedded. The localization of photogenerated charge carriers in a quantum dot along three directions.
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