Investigation of the spatial distribution of hot carriers in quantum-well structures via hyperspectral luminescence imaging

Esmaielpour, Hamidreza; Lombez, Laurent; Giteau, Maxime; Delamarre, Amaury; Ory, Daniel S.; Cattoni, Andréa; Collin, Stéphane; Guillemoles, Jean‐François; Suchet, Daniel

doi:10.1063/5.0022277

Cited by 12 publications

(15 citation statements)

References 45 publications

(65 reference statements)

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“…We have proposed an alternative method to extract the temperature in thin heterostructures 32 , where we consider the ratio between the PL spectra obtained at two different laser fluences labeled 1 and . Assuming the absorptivity at a given energy is independent of the absorbed power, we have ln (…”

Section: Methodsmentioning

confidence: 99%

Identification of surface and volume hot-carrier thermalization mechanisms in ultrathin GaAs layers

Giteau

Moustier

Suchet

et al. 2020

Journal of Applied Physics

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Hot-carrier solar cells offer the opportunity to harvest more energy than the limit set by the Shockley-Queisser model by reducing the losses due to the thermalization of photo-generated carriers. Previous reports have shown lower thermalization rates in thinner absorbers, but the origin of this phenomenon is not precisely understood. In this work, we investigate a series of ultrathin GaAs absorber layers sandwiched between AlGaAs barriers and transferred on host substrates with a gold back mirror. We perform power-dependent photoluminescence characterizations at different laser wavelengths from which we determine the carrier temperature in four absorber thicknesses between 20 and 200 nm. We observe a linear relationship between the absorbed power and the carrier temperature increase. By relating the absorbed and thermalized power, we extract a thermalization coefficient for all samples. It shows an affine dependence with the thickness, leading to the identification of distinct volume and surface contributions to thermalization. We confirm that volume thermalization is linked to LO phonon decay. We discuss the origin of the interface-related thermalization, showing that the effect of LO phonon transport is negligible. Overall, this work sheds new light on thermalization processes in ultrathin semiconductor layers and introduces a method to compare the performance of hot-carrier absorbers.

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Section: Methodsmentioning

confidence: 99%

Identification of surface and volume hot-carrier thermalization mechanisms in ultrathin GaAs layers

Giteau

Moustier

Suchet

et al. 2020

Journal of Applied Physics

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“…This approach is profusely described in the scientific literature, and some examples, applied in particular to semiconductor heterostructures, can be found in refs , , , , . Yet, attention must be paid in case of nonuniform layer absorptivity at energies above the band gap where this procedure might lead to an overestimation of the effective temperature. ,, …”

Section: Resultsmentioning

confidence: 99%

“…Significant progress has been achieved in the electronic structure engineering of nanoscopic systems, allowing for a thorough characterization of the charge carrier dynamics and correlation with the optical response. This is particularly crucial in semiconductor heterostructures like resonant tunneling diodes (RTDs) − where challenging questions still pervade the physics of carrier excitation, transport, relaxation, and recombination. − In particular, mapping the thermalization gradient along the transport path and how it is affected by external factors is still a relevant topic to be characterized and understood, and optical tools are well suited for this purpose. , …”

Section: Introductionmentioning

confidence: 99%

Optical Mapping of Nonequilibrium Charge Carriers

et al. 2021

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We investigate the energy relaxation segmentation in a resonant tunneling heterostructure by assessing the optical and transport dynamics of nonequilibrium charge carriers. The electrical and optical properties are analyzed using electronic transport measurements combined with electro- and photoluminescence spectroscopies in continuous-wave mode. Our results suggest that hot electron and hole populations form independent nonequilibrium systems that do not thermalize among them and with the lattice. Consequently, the carrier effective temperature changes independently at different regions of the heterostructure, with a population distribution for holes colder than for electrons.

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“…The active region (the QWs and barriers) of the sample is isolated by un‐doped InP cladding layers to improve the localization of photo‐generated carriers within the QWs. The description of the growth parameters is discussed elsewhere 19 . The InGaAs MQW structure has already shown evidence of hot carrier effects, 19–21 making it a suitable candidate for optical spectroscopy of hot carriers to study their properties in the system.…”

Section: Determination Of Carrier Temperature and Quasi‐fermi‐level S...mentioning

confidence: 99%

“…The hyperspectral imaging system provides vast information of photo‐generated hot carriers, such as their diffusion, spatial distribution, and thermoelectric effects. Some aspects of these effects have been studied in detail in the past 19,20 . By applying various calibration methods, the absolute photon flux emitted by the sample is determined 22 .…”

Section: Determination Of Carrier Temperature and Quasi‐fermi‐level S...mentioning

confidence: 99%

Impact of excitation energy on hot carrier properties in InGaAs multi‐quantum well structure

Esmaielpour¹,

Lombez

Giteau

et al. 2022

Progress in Photovoltaics

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Hot carrier solar cells aim to overcome the theoretical limit of single‐junction photovoltaic devices by suppressing the thermalization of hot carriers and extracting them through energy selective contacts. Designing efficient hot carrier absorbers requires further investigation on hot carrier properties in materials. Although the thermalization of hot carriers is responsible for a large portion of energy loss in solar cells, it is still one of the least understood phenomena in semiconductors. Here, the impact of excitation energy on the properties of photo‐generated hot carriers in an InGaAs multi‐quantum well (MQW) structure at various lattice temperatures and excitation powers is studied. Photoluminescence (PL) emission of the sample is detected by a hyperspectral luminescence imager, which creates spectrally and spatially resolved PL maps. The thermodynamic properties of hot carriers, such as temperature and quasi‐Fermi‐level splitting, are carefully determined via applying full PL spectrum fitting, which solves the Fermi–Dirac integral and considers the band‐filling effect in the nanostructured material. In addition, the impact of thermalized power density and carrier scattering with longitudinal optical phonons on the spectral linewidth broadening under two excitation energies is studied.

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Investigation of the spatial distribution of hot carriers in quantum-well structures via hyperspectral luminescence imaging

Abstract: Note: This paper is part of the Special Topic on Hot Electron Physics and Applications.

Cited by 12 publications

References 45 publications

Identification of surface and volume hot-carrier thermalization mechanisms in ultrathin GaAs layers

Identification of surface and volume hot-carrier thermalization mechanisms in ultrathin GaAs layers

Optical Mapping of Nonequilibrium Charge Carriers

Impact of excitation energy on hot carrier properties in InGaAs multi‐quantum well structure

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