Determination of energy difference and width of minibands in GaAs/AlGaAs superlattices by using Fourier transform photoreflectance and photoluminescence

Motyka, M.; Janiak, F.; Misiewicz, J.; Wasiak, Michał; Kosiel, Kamil; Bugajski, M.

doi:10.2478/s11772-011-0021-7

Cited by 7 publications

(3 citation statements)

References 15 publications

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“…Dashed lines represent the transition energies obtained from numerical calculations (where h(n)e(n) or l(n)e(n) notations means heavy (light) hole n-th level and electron n-th level). In this layout of superlattices layers designed as a QCL active region and injector, the energy width of the minibands is negligible, as distinct from the typical superlattices where and points related optical transitions might be observed (Motyka et al 2011b). There is a difference between ground state transition energies obtained from these two experiments (PR and PL), which can be better seen in Fig.…”

Section: Resultsmentioning

confidence: 88%

Advanced optical characterization of AlGaAs/GaAs superlattices for active regions in quantum cascade lasers

et al. 2014

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In this work, AlGaAs/GaAs superlattices with layer composition imitating the active region of quantum cascade lasers emitting in the mid infrared spectral range were investigated. Using optical spectroscopy techniques (photoreflectance and photoluminescence) together with numerical calculations performed within the effective mass approximation, we studied the band structure of the formed conduction minibands including the modification of the wave functions with the external electric field. In addition, the applied growth rates of the GaAs/AlGaAs superlattices have been verified by investigating the Stokes shift between the emission and absorption spectra. Finally, it has been shown that testing the structure imitating the operational laser device might be performed (without the electric field applied) by photoluminescence measurements realized within the Fourier Transformed Infrared Spectroscopy based concept.

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Section: Resultsmentioning

confidence: 88%

Advanced optical characterization of AlGaAs/GaAs superlattices for active regions in quantum cascade lasers

et al. 2014

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“…The dynamical diffraction theory has been used for simulating the symmetric (004) reflections leading to the extraction of structural parameters of periodic structures. An almost perfect planar uniformity of growth condi− tions of the "slow−grown" structures was proved by the photoluminescence (PL) and photoreflectance (PR) charac− terisation that was performed for superlattice test structures [16][17][18].…”

Section: Ex Situ Examinationmentioning

confidence: 99%

Multi-step interrupted-growth MBE technology for GaAs/AlGaAs (∼9.4 μm) room temperature operating quantum-cascade lasers

Kosiel

Kubacka-Traczyk

Sankowska

et al. 2012

Opto-Electronics Review

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In order to adjust the highly controllable and optimum growth conditions, the multi-step interrupted-growth MBE processes were performed to deposit a series of GaAs/Al0.45Ga0.55As QCL structures. The additional calibrations of MBE system were carried out during the designed growth interruptions. This solution was combined with a relatively low growth rate of active region layers, in order to suppress the negative effects of elemental flux instabilities. As a result, the fabricated QCL structures have yielded devices operating with peak optical power of ∼12 mW at room temperature. That is a better result than was obtained for comparable structures deposited with a growth rate kept constant, and with the only initial calibrations performed just before the epitaxy of the overall structure.

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“…Previously, we reported that photoluminescence (emission) and photoreflectance (high sensitivity absorption-like modulation technique), realized within a Fourier-transform (FT) spectrometer-based experimental configuration [11], can provide the information about the electronic structure of the AlGaAs/GaAs superlattices due to the possibility of detecting the interband and intersubband optical transitions [12]. Furthermore, these techniques were successfully employed to examine the growth rates accuracy by the analysis of the Stokes shift between the emission and absorption spectra of the active region of a mid-infrared QCL (at approx.…”

Section: Introductionmentioning

confidence: 99%

Optical Properties of Active Regions in Terahertz Quantum Cascade Lasers

Dyksik

Motyka

Rudno‐Rudziński

et al. 2016

J Infrared Milli Terahz Waves

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In this work, AlGaAs/GaAs superlattice, with layers' sequence and compositions imitating the active and injector regions of a quantum cascade laser designed for emission in the terahertz spectral range, was investigated. Three independent absorption-like optical spectroscopy techniques were employed in order to study the band structure of the minibands formed within the conduction band. Photoreflectance measurements provided information about interband transitions in the investigated system. Common transmission spectra revealed, in the target range of intraband transitions, mainly a number of lines associated with the phonon-related processes, including two-phonon absorption. In contrast, differential transmittance realized by means of Fourier-transform spectroscopy was utilized to probe the confined states of the conduction band. The obtained energy separation between the second and third confined electron levels, expected to be predominantly contributing to the lasing, was found to be~9 meV. The optical spectroscopy measurements were supported by numerical calculations performed in the effective mass approximation and XRD measurements for layers' width verification. The calculated energy spacings are in a good agreement with the experimental values.

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Determination of energy difference and width of minibands in GaAs/AlGaAs superlattices by using Fourier transform photoreflectance and photoluminescence

Cited by 7 publications

References 15 publications

Advanced optical characterization of AlGaAs/GaAs superlattices for active regions in quantum cascade lasers

Advanced optical characterization of AlGaAs/GaAs superlattices for active regions in quantum cascade lasers

Multi-step interrupted-growth MBE technology for GaAs/AlGaAs (∼9.4 μm) room temperature operating quantum-cascade lasers

Optical Properties of Active Regions in Terahertz Quantum Cascade Lasers

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