Impact of vertical inter-QDs spacing correlation with the strain energy in a coupled bilayer quantum dot heterostructure

Tongbram, Binita; Mandal, Ajay; Sengupta, Sourav; Chakrabarti, Subhananda

doi:10.1016/j.jallcom.2017.07.215

Cited by 16 publications

(4 citation statements)

References 29 publications

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“…We previously reported the advantages of having a smaller VIDS in coupled bilayer QDs and its correlation with the strain energy along the z direction in association with the dot density distribution in the coupled InAs QDs. 17 The higher the strain energy that propagates, the larger the QD size in the active layer. We determined the efficiency of strain energy propagation in terms of the vertical strain channel length (Ls).…”

Section: Resultsmentioning

confidence: 99%

“…Fluctuation in the strain propagation and its coupling potential depends on the vertical inter-QD spacing (VIDS). We previously reported the advantages of having a smaller VIDS in coupled bilayer QDs and its correlation with the strain energy along the z direction in association with the dot density distribution in the coupled InAs QDs . The higher the strain energy that propagates, the larger the QD size in the active layer.…”

Section: Results and Discussionmentioning

confidence: 99%

“…It opens new pathways for the application of InAs/GaAs QD heterostructures in telecommunication wavelengths ranging from 1.3 to 1.55 μm. 5 Recently, Stephan et al studied the response of self-assembled InAs/GaAs QDs to strong terahertz pulses tuned to the s-to-p transition. 6 In addition, a successful investigation on the lateral spacing of quantum coupling between InAs QDs demonstrated the maximum critical limit of the indium migration distance to be ∼30 nm; this study also presented the growth model of self-assembled InAs/GaAs QDs showing significant changes in the surface self-diffusion rate of indium adatoms.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, optimizing the VC stacked structures with GaAs spacer layers grown under different growth parameters is a challenging research topic. It opens new pathways for the application of InAs/GaAs QD heterostructures in telecommunication wavelengths ranging from 1.3 to 1.55 μm . Recently, Stephan et al studied the response of self-assembled InAs/GaAs QDs to strong terahertz pulses tuned to the s-to-p transition .…”

Section: Introductionmentioning

confidence: 99%

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Impact of an In_xGa_1–xAs Capping Layer in Impeding Indium Desorption from Vertically Coupled InAs/GaAs Quantum Dot Interfaces

Tongbram

Sengupta

Chakrabarti

2018

ACS Appl. Nano Mater.

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This study describes the effect of a thin GaAs spacer of 4.5 nm thickness in a bilayer-coupled InAs quantum dot (QD) heterostructure. Here, we report the first demonstration of InAs/GaAs QDs capped by self-assembled In x Ga1–x As layers. Self-assembled In x Ga1–x As layers were introduced into each intermediate layer across the interface of InAs QDs and the GaAs layer in a vertical-coupled bilayer QD (VCBQD) heterostructure to prevent indium desorption from the QDs. A change in the indium content in the seed-layer InAs QDs changes the self-assembly position and modifies the In x Ga1–x As layer thickness. A theoretical approach was presented to study the formation of self-assembled In x Ga1–x As layers at each strain-free layer. We showed that the strain energy at the second intermediate (ε zz2) layer is greater than that at the first intermediate (ε zz1) layer; ε zz2 depends on the vertical strain channel length. The impact of the In x Ga1–x As layer thickness on the strain energy was studied using high-resolution transmission electron microscopy; a shorter strain channel length was found to facilitate the formation of a more relaxed and larger-sized self-assembled In x Ga1–x As layer in the active layer. This In x Ga1–x As layer formed at the intermediate layer acts as a capping layer or a protective shield for the indium adatoms, preventing their desorption from the InAs QDs. Furthermore, we studied the thermal stability of the self-assembled In x Ga1–x As layer by annealing the VCBQD samples at 700 and 800 °C. This aspect has been investigated for the first time ever in a study of the coupling efficiency between the InAs QDs and In x Ga1–x As capping layer. A high-resolution in-plane (2θχ/ϕ) reciprocal space mapping (RSM) technique provided the connection between the in-plane reciprocal lattice point of the InAs QDs and In x Ga1–x As layers and revealed the strain and coupling between them. InAs QDs fully covered with the self-assembled In x Ga1–x As layer enhanced the photoluminescence intensity by 77% and had an activation energy of 467 meV.

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Section: Resultsmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of an In_xGa_1–xAs Capping Layer in Impeding Indium Desorption from Vertically Coupled InAs/GaAs Quantum Dot Interfaces

Tongbram

Sengupta

Chakrabarti

2018

ACS Appl. Nano Mater.

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InAs quantum dot-in-a-well heterostructures with InGaAs, GaAsN and GaAsSb well using digital alloy capping layer

Kumar

Saha

Tongbram

et al. 2023

Current Applied Physics

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Subsiding strain-induced In-Ga intermixing in InAs/In Ga1−As sub-monolayer quantum dots for room temperature photodetectors

Chakrabarti

Gourishetty

Panda

et al. 2022

Infrared Physics & Technology

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Impact of vertical inter-QDs spacing correlation with the strain energy in a coupled bilayer quantum dot heterostructure

Cited by 16 publications

References 29 publications

Impact of an In_xGa_1–xAs Capping Layer in Impeding Indium Desorption from Vertically Coupled InAs/GaAs Quantum Dot Interfaces

Impact of an In_xGa_1–xAs Capping Layer in Impeding Indium Desorption from Vertically Coupled InAs/GaAs Quantum Dot Interfaces

InAs quantum dot-in-a-well heterostructures with InGaAs, GaAsN and GaAsSb well using digital alloy capping layer

Subsiding strain-induced In-Ga intermixing in InAs/In Ga1−As sub-monolayer quantum dots for room temperature photodetectors

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Impact of vertical inter-QDs spacing correlation with the strain energy in a coupled bilayer quantum dot heterostructure

Cited by 16 publications

References 29 publications

Impact of an InxGa1–xAs Capping Layer in Impeding Indium Desorption from Vertically Coupled InAs/GaAs Quantum Dot Interfaces

Impact of an InxGa1–xAs Capping Layer in Impeding Indium Desorption from Vertically Coupled InAs/GaAs Quantum Dot Interfaces

InAs quantum dot-in-a-well heterostructures with InGaAs, GaAsN and GaAsSb well using digital alloy capping layer

Subsiding strain-induced In-Ga intermixing in InAs/In Ga1−As sub-monolayer quantum dots for room temperature photodetectors

Contact Info

Product

Resources

About

Impact of an In_xGa_1–xAs Capping Layer in Impeding Indium Desorption from Vertically Coupled InAs/GaAs Quantum Dot Interfaces

Impact of an In_xGa_1–xAs Capping Layer in Impeding Indium Desorption from Vertically Coupled InAs/GaAs Quantum Dot Interfaces