Impact of Digital Alloy Capping Layers on Bilayer InAs Quantum Dot Heterostructures

Kumar, Rohit; Saha, Jhuma; Chakrabarti, Subhananda

doi:10.1109/tnano.2020.2993690

Cited by 4 publications

(2 citation statements)

References 28 publications

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“…The capping layer can be deposited over the QDs in many ways, viz. conventional capping, digital alloy capping [6][7][8][9], and linear alloy capping [10,11]. In the linear alloy approach, the composition of capping material is decreasing linearly from the apex of QD towards the top GaAs layer.…”

Section: Introductionmentioning

confidence: 99%

Impact of linear alloy on strain coupled bilayer InAs/GaAs1-ySby quantum dot heterostructures

Kumar¹,

Saha²,

Chakrabarti³

2023

Physics and Simulation of Optoelectronic Devices XXXI

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In this work, the concept of the novel approach called linear alloy capping layer (LACL) has been investigated on the strain-coupled bilayer InAs/GaAs1-ySby QD heterostructures. Here, two analog structures with low (structure BA1) and high (structure BA2) antimony (Sb) contents, and one linear alloyed structure (BL) with varying Sb-content inside the capping layer is considered. The Sb-content inside the CL of structure BA1 and BA2 are 10% and 20%, respectively. Whereas, it is varying linearly from 20% to 10% inside structure BL. The CL and GaAs spacer layer thickness has been taken as 8 nm and 13 nm, respectively. All these three structures have been modeled using Nextnano++ simulation software. Two strain components, hydrostatic and biaxial have been computed and compared. These two strain components help in decreasing the ground state energy gap which leads to a red-shifted PL emission. The structure BL offers improved biaxial strain by 1.11% and 0.56% inside QD compared to structures BA1 and BA2. In addition, the magnitude of hydrostatic strain inside QD of structure BL is reduced by 1.78% and increased by 0.64% compared to structures BA1 and BA2. The strain inside the CL of structure BL is reduced very smoothly in a linear fashion as compared to other analog structures. The computed PL emission of structures BA1, BA2, and BL are 1371 nm, 1665 nm, and 1617 nm, respectively. Also, the proposed structure BL offers a type-II band profile. Hence this proposed approach is useful for future optoelectronic applications.

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Section: Introductionmentioning

confidence: 99%

Impact of linear alloy on strain coupled bilayer InAs/GaAs1-ySby quantum dot heterostructures

Kumar¹,

Saha²,

Chakrabarti³

2023

Physics and Simulation of Optoelectronic Devices XXXI

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“…[13] The n type conductivity can be linked with the oxygen vacancies (Vos) present in the Ga2O3 matrix, which can act as shallow donors. [14] Furthermore, β-Ga2O3 demonstrates strong room-temperature (RT) photoluminescence (PL) which can be tuned for its potential application as phosphor of LEDs. [11] In spite of its interesting material properties, complex optical processes involved in β-Ga2O3 restricts its application towards deep-UV photodetector and light emitters.…”

Section: Introductionmentioning

confidence: 99%

Oxygen mediated optical and electrical property modification of RF sputtered Ga2O3 thin films for photodetector application

Bhowmick

Saha

Mishra

et al. 2022

Nanoengineering: Fabrication, Properties, Optics, Thin Films, and Devices XIX

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The deep UV photodetectors (DUV-PDs) are technologically important for diverse applications, ranging from environmental monitoring, space communication etc. Among all solar blind materials Ga2O3 thin film shows its strong contention owing to its intrinsic solar-blind nature. However, the PD’s efficiency can be significantly affected by the defects such as oxygen vacancies (VO). Both the deficiency and surplus of oxygen during Ga2O3 thin film deposition can result in the formation of carrier scattering centers, sub-bandgap absorption, and leakage channels. In this work, we have studied the impact of oxygen flow rate (OFR) on the optical and electrical properties of RF sputtered Ga2O3 thin film. The Ga2O3 thin films were deposited on p-Si at room temperature, where the Ar to O2 ratio has been varied from 1:0, 1:1, to 1:2 to maintain the O2 poor and O2 rich condition. The XRD spectrum shows the presence of two peaks positioned at ~33.0° , and ~64.5° , which are further identified as β(-202), and β(-313), respectively for samples grown without oxygen. The top view FESEM images confirm the uniform film growth for both O2 rich conditions while some isolated bubble-like and grain-like structures are witnessed in ratios 1:0, and 1:1, respectively. The change in optical bandgap for all the samples is determined using diffuse reflectance spectra which show the bandgap values lie in the range of 4.1 eV-4.2 eV. Furthermore, the deconvoluted photoluminescence spectra (in the range of λ=300-500 nm) show the change in different types of Vo defects originating due to OFR induced structural asymmetry in the Ga2O3 thin film. Finally, the change in dark current in Ga2O3/p-Si heterojunctions is estimated from current-voltage (I-V) characteristics to understand the effect of OFR on its electrical properties for future DUV detectors.

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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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Impact of Digital Alloy Capping Layers on Bilayer InAs Quantum Dot Heterostructures

Cited by 4 publications

References 28 publications

Impact of linear alloy on strain coupled bilayer InAs/GaAs1-ySby quantum dot heterostructures

Impact of linear alloy on strain coupled bilayer InAs/GaAs1-ySby quantum dot heterostructures

Oxygen mediated optical and electrical property modification of RF sputtered Ga2O3 thin films for photodetector application

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

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