Electrons, Localization but no Hopping: Disorder as Key for Understanding Charge Transport in Mesoporous Silicon

This article presents a unique study on the charge carrier transport in electrochemically anodized mesoporous silicon by combining macroscopic conductivity and thermopower measurements. Temperature‐dependent electrical conductivity measurements reveal a thermally activated transport in extended elec...

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Main Authors: Tommy Hofmann, Haider Haseeb, Danny Kojda, Natalia Gostkowska‐Lekner, Klaus Habicht
Format: Article
Language:English
Published: Wiley-VCH 2025-04-01
Series:Small Structures
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Online Access:https://doi.org/10.1002/sstr.202400437
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author Tommy Hofmann
Haider Haseeb
Danny Kojda
Natalia Gostkowska‐Lekner
Klaus Habicht
author_facet Tommy Hofmann
Haider Haseeb
Danny Kojda
Natalia Gostkowska‐Lekner
Klaus Habicht
author_sort Tommy Hofmann
collection DOAJ
description This article presents a unique study on the charge carrier transport in electrochemically anodized mesoporous silicon by combining macroscopic conductivity and thermopower measurements. Temperature‐dependent electrical conductivity measurements reveal a thermally activated transport in extended electronic states. An intrinsic variation of the thermal activation energies from sample to sample upon apparent identical synthesis conditions is discussed in terms of microscopic disorder. In a detailed analysis of the activation energies, the existence of a disorder‐dependent mobility edge between localized and extended states in a band tail with exponential density‐of‐states becomes indispensable for understanding the microscopic transport mechanism. The observation of a Meyer–Neldel compensation rule for the conductivity between different samples is a direct consequence of this mobility edge. Temperature‐dependent thermopower measurements provide further, stringent proof for disorder‐dominated transport in extended states above the mobility edge and dispel an alternative explanation attempt for the Meyer–Neldel rule in mesoporous silicon based on multiphonon absorption upon charge carrier transport.
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spelling doaj-art-c21db87655a24ff9a6f52d7e6f244cf02025-08-20T03:08:50ZengWiley-VCHSmall Structures2688-40622025-04-0164n/an/a10.1002/sstr.202400437Electrons, Localization but no Hopping: Disorder as Key for Understanding Charge Transport in Mesoporous SiliconTommy Hofmann0Haider Haseeb1Danny Kojda2Natalia Gostkowska‐Lekner3Klaus Habicht4Department Dynamics and Transport in Quantum Materials Helmholtz‐Zentrum Berlin für Materialien und Energie GmbH Hahn‐Meitner‐Platz 1 14109 Berlin GermanyDepartment Dynamics and Transport in Quantum Materials Helmholtz‐Zentrum Berlin für Materialien und Energie GmbH Hahn‐Meitner‐Platz 1 14109 Berlin GermanyDepartment Dynamics and Transport in Quantum Materials Helmholtz‐Zentrum Berlin für Materialien und Energie GmbH Hahn‐Meitner‐Platz 1 14109 Berlin GermanyDepartment Dynamics and Transport in Quantum Materials Helmholtz‐Zentrum Berlin für Materialien und Energie GmbH Hahn‐Meitner‐Platz 1 14109 Berlin GermanyDepartment Dynamics and Transport in Quantum Materials Helmholtz‐Zentrum Berlin für Materialien und Energie GmbH Hahn‐Meitner‐Platz 1 14109 Berlin GermanyThis article presents a unique study on the charge carrier transport in electrochemically anodized mesoporous silicon by combining macroscopic conductivity and thermopower measurements. Temperature‐dependent electrical conductivity measurements reveal a thermally activated transport in extended electronic states. An intrinsic variation of the thermal activation energies from sample to sample upon apparent identical synthesis conditions is discussed in terms of microscopic disorder. In a detailed analysis of the activation energies, the existence of a disorder‐dependent mobility edge between localized and extended states in a band tail with exponential density‐of‐states becomes indispensable for understanding the microscopic transport mechanism. The observation of a Meyer–Neldel compensation rule for the conductivity between different samples is a direct consequence of this mobility edge. Temperature‐dependent thermopower measurements provide further, stringent proof for disorder‐dominated transport in extended states above the mobility edge and dispel an alternative explanation attempt for the Meyer–Neldel rule in mesoporous silicon based on multiphonon absorption upon charge carrier transport.https://doi.org/10.1002/sstr.202400437disorderlocalizationmobility edgenanostructuresilicon
spellingShingle Tommy Hofmann
Haider Haseeb
Danny Kojda
Natalia Gostkowska‐Lekner
Klaus Habicht
Electrons, Localization but no Hopping: Disorder as Key for Understanding Charge Transport in Mesoporous Silicon
Small Structures
disorder
localization
mobility edge
nanostructure
silicon
title Electrons, Localization but no Hopping: Disorder as Key for Understanding Charge Transport in Mesoporous Silicon
title_full Electrons, Localization but no Hopping: Disorder as Key for Understanding Charge Transport in Mesoporous Silicon
title_fullStr Electrons, Localization but no Hopping: Disorder as Key for Understanding Charge Transport in Mesoporous Silicon
title_full_unstemmed Electrons, Localization but no Hopping: Disorder as Key for Understanding Charge Transport in Mesoporous Silicon
title_short Electrons, Localization but no Hopping: Disorder as Key for Understanding Charge Transport in Mesoporous Silicon
title_sort electrons localization but no hopping disorder as key for understanding charge transport in mesoporous silicon
topic disorder
localization
mobility edge
nanostructure
silicon
url https://doi.org/10.1002/sstr.202400437
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AT dannykojda electronslocalizationbutnohoppingdisorderaskeyforunderstandingchargetransportinmesoporoussilicon
AT nataliagostkowskalekner electronslocalizationbutnohoppingdisorderaskeyforunderstandingchargetransportinmesoporoussilicon
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