Electrochemical Liquid–Liquid–Solid Crystal Growth of Germanium Microwires on Hard and Soft Conductive Substrates at Low Temperature in Aqueous Solution

Fahrenkrug, Eli; Biehl, Janelle; Maldonado, Stephen

doi:10.1021/acs.chemmater.5b00644

Cited by 26 publications

(53 citation statements)

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“…To demonstrate this concept, a strategy to prepare liquid metal microdroplets was developed. 36 Conventional photolithography was combined with simple doctor blading to create large-area arrays (>1 cm 2 ) of discrete liquid metal microelectrodes. Figure 4a−g shows the general premise and subsequent application in ec-LLS.…”

Section: Ec-lls Synthesis Of Crystalline Group IV Semiconductorsmentioning

confidence: 99%

Electrochemical Liquid–Liquid–Solid (ec-LLS) Crystal Growth: A Low-Temperature Strategy for Covalent Semiconductor Crystal Growth

Fahrenkrug

Maldonado

2015

Acc. Chem. Res.

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This Account describes a new electrochemical synthetic strategy for direct growth of crystalline covalent group IV and III-V semiconductor materials at or near ambient temperature conditions. This strategy, which we call "electrochemical liquid-liquid-solid" (ec-LLS) crystal growth, marries the semiconductor solvation properties of liquid metal melts with the utility and simplicity of conventional electrodeposition. A low-temperature liquid metal (i.e., Hg, Ga, or alloy thereof) acts simultaneously as the source of electrons for the heterogeneous reduction of oxidized semiconductor precursors dissolved in an electrolyte as well as the solvent for dissolution of the zero-valent semiconductor. Supersaturation of the semiconductor in the liquid metal triggers eventual crystal nucleation and growth. In this way, the liquid electrolyte-liquid metal-solid crystal phase boundary strongly influences crystal growth. As a synthetic strategy, ec-LLS has several intrinsic features that are attractive for preparing covalent semiconductor crystals. First, ec-LLS does not require high temperatures, toxic precursors, or high-energy-density semiconductor reagents. This largely simplifies equipment complexity and expense. In practice, ec-LLS can be performed with only a beaker filled with electrolyte and an electrical circuit capable of supplying a defined current (e.g., a battery in series with a resistor). By this same token, ec-LLS is compatible with thermally and chemically sensitive substrates (e.g., plastics) that cannot be used as deposition substrates in conventional syntheses of covalent semiconductors. Second, ec-LLS affords control over a host of crystal shapes and sizes through simple changes in common experimental parameters. As described in detail herein, large and small semiconductor crystals can be grown both homogeneously within a liquid metal electrode and heterogeneously at the interface of a liquid metal electrode and a seed substrate, depending on the particular details chosen for ec-LLS. Third, the rate of introduction of zero-valent materials into the liquid metal is precisely gated with a high degree of resolution by the applied potential/current. The intent of this Account is to summarize the key elements of ec-LLS identified to date, first contextualizing this method with respect to other semiconductor crystal growth methods and then highlighting some unique capabilities of ec-LLS. Specifically, we detail ec-LLS as a platform to prepare Ge and Si crystals from bulk- (∼1 cm(3)), micro- (∼10(-10) cm(3)), and nano-sized (∼10(-16) cm(3)) liquid metal electrodes in common solvents at low temperature. In addition, we describe our successes in the preparation of more compositionally complex binary covalent III-V semiconductors.

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Section: Ec-lls Synthesis Of Crystalline Group IV Semiconductorsmentioning

confidence: 99%

Electrochemical Liquid–Liquid–Solid (ec-LLS) Crystal Growth: A Low-Temperature Strategy for Covalent Semiconductor Crystal Growth

Fahrenkrug

Maldonado

2015

Acc. Chem. Res.

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“…Таким образом, отсутствие роста на Sn и его наличие на In, а также сопоставление полученных нами экспериментальных ре-зультатов с результатами работ [12,13,15] указывают на то, что основополагающую роль для синтеза нитевидных нанокристаллов Ge из водного раствора является нали-чие частиц металла в жидком состоянии.…”

Section: Discussionunclassified

“…В работах [12,13] была продемонстрирована возмож-ность электрохимического осаждения нитевидных на-ноструктур Ge из водных растворов без использова-ния темплатов. Особенностью этого метода является использование расплавленных частиц металлов, таких как Hg и Ga, в качестве центров кристаллизации.…”

Section: Introductionunclassified

“…Особенностью этого метода является использование расплавленных частиц металлов, таких как Hg и Ga, в качестве центров кристаллизации. Ав-торы работ [12,13] считают, что жидкий металл служит электродом для восстановления ионов, содержащих Ge, до германия в атомарном состоянии, с их последующим растворением и образованием расплава эвтектическо-го состава. Непрерывная реакция катодного восстанов-ления обеспечивает концентрационное перенасыщение расплава германием, в результате чего происходит кри-сталлизация Ge в расплаве на границе с подложкой.…”

Section: Introductionunclassified

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Влияние температуры электролита на процесс катодного осаждения нитевидных наноструктур Ge из водных растворов на частицах In и Sn

Гаврилин¹,

Громов²,

Дронов³

et al. 2017

Физика И Техника Полупроводников

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Представлены результаты исследования роста нитевидных структур Ge из водных растворов электролитов при различных температурах с использованием массивов наночастиц In и Sn в качестве центров кристалли-зации. Температура процесса катодного осаждения Ge из водных растворов оказывает существенное влияние на строение слоя, осаждаемого на поверхность. При наличии частиц металлов в расплавленном состоянии происходит рост нитевидных структур Ge за счет катодного восстановления ионов, содержащих Ge, на поверхности электрода с последующим растворением и кристаллизацией в расплаве на границе с подложкой. Полученные результаты показывают решающую роль наличия жидких частиц металла в процессе электрохимического формирования нитевидных нанокристаллов германия.

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“…8,9 A newly identified method is electrochemical liquid-liquid-solid (ec-LLS) crystal growth, where a liquid metal electrode acts both as the source of electrons for heterogeneous reduction reactions and as the solvent for semiconductor crystal formation. 10,11 An advantage of ec-LLS over the aforementioned methods is the capacity to produce crystalline semiconductor micro/nanowires in aqueous solution at ambient temperatures and pressures.…”

mentioning

confidence: 99%

Electrochemical Liquid-Liquid-Solid Deposition of Ge at Hg Microdroplet Ultramicroelectrodes

Zhang¹,

Fahrenkrug²,

Maldonado³

2016

J. Electrochem. Soc.

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Individual Hg microdroplet electrodes were used to perform Ge electrochemical liquid-liquid-solid (ec-LLS) crystal growth in aqueous solutions containing dissolved GeO2. The Hg microdroplets were prepared by electrodeposition of Hg onto pre-existing Pt ultramicroelectrodes (r < 10 μm). These Hg microdroplet ultramicroelectrode platforms were then used for analyses of Ge ec-LLS by both voltammetry and amperometry. Voltammetric responses indicated that Ge was neither immediately nor quantitatively dissolved into Hg upon electroreduction of aqueous solutions of GeO2. Separately, chronoamperometry performed at large overpotentials for reduction of dissolved GeO2 yielded crystalline Ge but with notable differences as compared to ec-LLS at a bulk Hg pool electrode. One set of experiments featured the surface of the Hg microdroplets possessing a complete Ge shell. The data suggested this shell formed within the first 1000 s and essentially passivated the electrode against further heterogeneous GeO2 reduction but allowed limited H+ reduction. The other set of experiments exhibited a similar shell but with fissures or cracks that exposed fresh Hg to the electrolyte and allowed Ge electrodeposition to persist much longer. In these experiments, hollow, spiral crystalline Ge tubes were extruded from the interior of the Hg microdroplets.

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Electrochemical Liquid–Liquid–Solid Crystal Growth of Germanium Microwires on Hard and Soft Conductive Substrates at Low Temperature in Aqueous Solution

Cited by 26 publications

References 50 publications

Electrochemical Liquid–Liquid–Solid (ec-LLS) Crystal Growth: A Low-Temperature Strategy for Covalent Semiconductor Crystal Growth

Electrochemical Liquid–Liquid–Solid (ec-LLS) Crystal Growth: A Low-Temperature Strategy for Covalent Semiconductor Crystal Growth

Влияние температуры электролита на процесс катодного осаждения нитевидных наноструктур Ge из водных растворов на частицах In и Sn

Electrochemical Liquid-Liquid-Solid Deposition of Ge at Hg Microdroplet Ultramicroelectrodes

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