<?xml version="1.0" encoding="utf-8"?>
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  <doc>
    <id>21984</id>
    <completedYear/>
    <publishedYear>2018</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>11</pageFirst>
    <pageLast>20</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>articlenr</type>
    <publisherName>The Norwegian University of Science and Technology</publisherName>
    <publisherPlace>Trondheim</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2018-06-21</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">The impact of lattice strain on the reactivity of silicon</title>
    <abstract language="eng">The present study is focused on the question of how lattice strain mechanically introduced into silicon alters the chemical reactivity of the silicon atoms that are affected by the strain field on a microscopic length scale. The magnitude and local distribution of lattice strain are extracted from confocal Raman microscopy measurements. The reactivity of Si is expressed by the etch rate of Si after treatment with HF–HNO3–H2SiF6 mixtures. Then, the local etch rate is calculated from the local etch depth as determined by confocal microscopy. It has been found that tensile strain leads to the highest enhancement of the etch rate, followed by a compressive strain increase in the etch rate.</abstract>
    <parentTitle language="eng">Silicon for the Chemical and Solar Industry XIV</parentTitle>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <author>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </author>
    <editor>
      <firstName>Birger</firstName>
      <lastName>Andresen</lastName>
    </editor>
    <submitter>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </submitter>
    <author>
      <firstName>Tim</firstName>
      <lastName>Sieber</lastName>
    </author>
    <editor>
      <firstName>Lars</firstName>
      <lastName>Nygaard</lastName>
    </editor>
    <author>
      <firstName>Thomas</firstName>
      <lastName>Langner</lastName>
    </author>
    <editor>
      <firstName>Harry</firstName>
      <lastName>Rong</lastName>
    </editor>
    <author>
      <firstName>Steven</firstName>
      <lastName>Herold</lastName>
    </author>
    <editor>
      <firstName>Merete</firstName>
      <lastName>Tangstad</lastName>
    </editor>
    <editor>
      <firstName>Halvard</firstName>
      <lastName>Tveit</lastName>
    </editor>
    <editor>
      <firstName>Ingrid Gamst</firstName>
      <lastName>Page</lastName>
    </editor>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>silicon</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>etching</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Raman spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>lattice strain</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>stress</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>mechanical activation</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>mechanochemistry</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>confocal microscopy</value>
    </subject>
    <collection role="institutes" number="2206">FG Physikalische Chemie</collection>
  </doc>
  <doc>
    <id>23410</id>
    <completedYear/>
    <publishedYear>2018</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>conferenceobject</type>
    <publisherName>Universität des Saarlandes</publisherName>
    <publisherPlace>Saarbrücken</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2019-01-28</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Raman spectroscopic study on the formation of Cu3Si</title>
    <abstract language="eng">The term “direct synthesis” is defined in the literature as the reactions between silicon and methyl chloride, hydrogen chloride and other reagents like chlorobenzene and ethyl chloride to yield various alkyl- or aryl substituted chlorosilanes.[1] These reactions have two features in common: (1) The reactivity of silicon - in terms of reaction start temperature, reaction rate and silane product distribution - is originated and controlled by the interaction with metals. (2) The reaction is fully under kinetic control since the formed silanes are the thermodynamically least stable products in the system Si-H-Cl-C.[2] Several authors consider Cu3Si as the catalytically active phase in the direct synthesis. It is assumed, that CuCl formed under the conditions of the direct synthesis reacts with Si according to Eq. 1 and 2 to yield Cu3Si.[1]&#13;
     (1)    and            (2)&#13;
The present work describes a Raman microscopic study of the reaction of Si with Cu and CuCl with special emphasize given to the identification of the Cu3Si phase and the processes occurring in the surrounding bulk Si. There is one pathway in which a solid state reaction[3] between Si and CuCl leads to a massive nucleation of Cu3Si exactly at the position of the Si/CuCl solid-solid interface. The nucleation of Cu3Si creates such an enormous lattice strain so that several high-pressure modifications of Si can be identified at the reaction site and around. The second reaction pathway is controlled by a gas phase transport of CuCl at low temperatures. This transport pathway leads to a spread of Cu in nearest neighborhood close to the CuCl particles as well to a long range transport leading to a nucleation of microscopic Cu3Si precipitates away from the CuCl particles. Further studies on the reactivity of the Cu3Si containing reaction sites were performed and will be discussed in the presentation.</abstract>
    <parentTitle language="eng">9th European Silicon Days, 9-12 September 2018, Saarbrücken, Germany, Book of abstracts</parentTitle>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <author>
      <firstName>André</firstName>
      <lastName>Meißner</lastName>
    </author>
    <editor>
      <firstName>David</firstName>
      <lastName>Scheschkewitz</lastName>
    </editor>
    <submitter>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </submitter>
    <author>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </author>
    <editor>
      <firstName>Guido</firstName>
      <lastName>Kickelbick</lastName>
    </editor>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Raman spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>silicon</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>lattice strain</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>copper silicide</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>direct synthesis</value>
    </subject>
    <collection role="institutes" number="2206">FG Physikalische Chemie</collection>
  </doc>
  <doc>
    <id>23411</id>
    <completedYear/>
    <publishedYear>2018</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>S. 201</pageFirst>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>conferenceobject</type>
    <publisherName>Universität des Saarlandes</publisherName>
    <publisherPlace>Saarbrücken</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2019-01-28</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Lattice strain controls the etching of solar wafer surfaces</title>
    <abstract language="eng">Multi-wire sawing using an abrasive SiC slurry or diamond wires constitutes the main slicing techniques for multi- and monocrystalline silicon crystals in photovoltaics. The massive mechanical load during the sawing process creates a wafer surface layer characterized by lattice defects, pits, fractures, rifts, cracks, amorphous Si and even some high-pressure Si modifications, otherwise known as saw damage.[1] This highly defect-rich surface causes the rapid recombination of electron-hole pairs, requiring that it be removed by etching in order to manufacture solar cells and to generate a surface morphology having a low reflectivity which directly affects the solar cell’s efficiency.&#13;
However, etching of the saw damage features of a heterogeneous and laterally unevenly distributed etch attack and a significantly higher etch rate compared to the underlying bulk silicon.[2,3] The present study is focused on the question of how mechanically introduced lattice strain in single-crystalline silicon alters the chemical reactivity of the silicon atoms affected by the strain field on a microscopic length scale. The magnitude and local distribution of lattice strain were extracted from confocal Raman microscopy measurements according to Ref. 4. One of the parameters used to describe the reactivity of silicon is the local etch rate, which was derived from the local removal before and after etching by confocal microscopy. Wet-chemical etching was performed with HF-HNO3-H2SiF6 acid mixtures of different concentrations. It was found, that the reactivity of silicon increased linearly with the magnitude of lattice strain. In particular, an increase in tensile strain led to a higher increase in reactivity compared to the increase observed with growing compressive strain. The second decisive parameter is the reactivity of the etch mixture. Diluted acid mixtures with a low reactivity attack only the highest strained Si, whereas more concentrated and therefore more reactive acid mixtures are able to attack even slightly strained Si. Side effects, such as the behavior of amorphous or nanocrystalline Si and the generation of highly reactive intermediary species while etching, are discussed.</abstract>
    <parentTitle language="eng">9th European Silicon Days, 9-12 September 2018, Saarbrücken, Germany, Book of abstracts</parentTitle>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">false</enrichment>
    <author>
      <firstName>Thomas</firstName>
      <lastName>Langner</lastName>
    </author>
    <editor>
      <firstName>David</firstName>
      <lastName>Scheschkewitz</lastName>
    </editor>
    <submitter>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </submitter>
    <author>
      <firstName>Tim</firstName>
      <lastName>Sieber</lastName>
    </author>
    <editor>
      <firstName>Guido</firstName>
      <lastName>Kickelbick</lastName>
    </editor>
    <author>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Raman spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>silicon</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>lattice strain</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>etching</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>confocal microscopy</value>
    </subject>
    <collection role="institutes" number="2206">FG Physikalische Chemie</collection>
  </doc>
  <doc>
    <id>23413</id>
    <completedYear/>
    <publishedYear>2018</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>S. 198</pageFirst>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>conferenceobject</type>
    <publisherName>Universität des Saarlandes</publisherName>
    <publisherPlace>Saarbrücken</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2019-01-28</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">The influence of lattice deformations on the etch rates of potassium hydroxide on silicon</title>
    <abstract language="eng">One of the most common methods to analyse silicon materials is Raman-spectroscopy.[1] More recently there is a focus in the analysis of lattice deformations during sample preparations.[2] These deformations not only increase the chance of crack formation but also increases the chemical reactivity of the silicon towards etch processes or oxidation processes.[3] In this contribution, we will present our latest results on the influence of lattice deformations induced by scratches and saw damage on the etch rate of potassium hydroxide. The lattice deformation will be measured using Raman-microscopy and correlated with the height difference measured with confocal microscopy. It will be shown that the etch rate strongly depends on the lattice deformation and that the etch rate will increase by up to the factor 10 in areas with tensile deformation.</abstract>
    <parentTitle language="eng">9th European Silicon Days, 9-12 September 2018, Saarbrücken, Germany, Book of abstracts</parentTitle>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">false</enrichment>
    <author>
      <firstName>Steven</firstName>
      <lastName>Herold</lastName>
    </author>
    <editor>
      <firstName>David</firstName>
      <lastName>Scheschkewitz</lastName>
    </editor>
    <submitter>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </submitter>
    <author>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </author>
    <editor>
      <firstName>Guido</firstName>
      <lastName>Kickelbick</lastName>
    </editor>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>silicon</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>etching</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Raman spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>lattice strain</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>saw damage</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>confocal microscopy</value>
    </subject>
    <collection role="institutes" number="2206">FG Physikalische Chemie</collection>
  </doc>
  <doc>
    <id>23417</id>
    <completedYear/>
    <publishedYear>2018</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>S. 199</pageFirst>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>conferenceobject</type>
    <publisherName>Universität des Saarlandes</publisherName>
    <publisherPlace>Saarbrücken</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2019-01-28</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Dissolution of silicon in HF/HNO3 mixtures: A revised model</title>
    <abstract language="eng">The dissolution of Si in HF/HNO3 consists of a set of complex reactions and thus a large number of reaction products. The most comprehensive picture of this reaction, the role of the involved reaction products and the reactivity of the HF/HNO3 mixtures depending on their composition is drawn by Steinert et al..[1]-[3] Based on the first systematic investigations on hydrogen formation by Hoffmann et al.[4], Acker et al. succeeded a first mass and electron balance for the reaction of silicon in HF/HNO3.[5] However, there is still a lack in interpretation of the mass end electron balances arising from several nitrous oxides. So far, the identified nitrogen oxides NO, NO2 and N2O were considered in sum[5] and neither separated nor individually studied or quantified.  &#13;
The aim of this work is to complete the mass and electron balance by the contribution of the individual nitrous oxides and to identify their individual formation pathways. Kinetic measurements of the NO and NO2 formation during the dissolution of Si, NO2 turns out as a result from the oxidation of the primary product NO by the HNO3 in the etching mixtures. Subsequently, NO and NO2 react to N2O3 dissolved in the acid mixture. The kinetics of both reactions were individually studied by bubbling NO in HF/HNO3 mixtures of different composition. The already identified intermediary species N4O62+ turns out to be formed by disproportionation of dissolved NO2 via N2O4 without dissolution of silicon. A detailed kinetic studied showed, that only dissolved N2O3 and not the intermediate N4O62+ contribute to the dissolution rate of silicon in HF/HNO3 acid mixtures. Finally, kinetic measurements revealed that the formed H2 reduces gaseous NO yielding to the final gaseous reaction products N2, N2O as well as to ammonium ions which all are formed with identical reaction rate. This reaction is assumed to proceed via NH2OH as intermediate.&#13;
As result of the identification and quantification of intermediary and final reaction products a new reaction scheme needs to be established leading to a new approach to the mass and electron balance for the oxidation of silicon during the dissolution in HF/HNO3 mixtures.</abstract>
    <parentTitle language="eng">9th European Silicon Days, 9-12 September 2018, Saarbrücken, Germany, Book of abstracts</parentTitle>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">false</enrichment>
    <author>
      <firstName>Anja</firstName>
      <lastName>Rietig</lastName>
    </author>
    <editor>
      <firstName>David</firstName>
      <lastName>Scheschkewitz</lastName>
    </editor>
    <submitter>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </submitter>
    <author>
      <firstName>Thomas</firstName>
      <lastName>Langner</lastName>
    </author>
    <editor>
      <firstName>Guido</firstName>
      <lastName>Kickelbick</lastName>
    </editor>
    <author>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>silicon</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>etching</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Raman spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>mass spectrometry</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>gas analysis</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>reaction mechanism</value>
    </subject>
    <collection role="institutes" number="2206">FG Physikalische Chemie</collection>
  </doc>
  <doc>
    <id>23502</id>
    <completedYear/>
    <publishedYear>2019</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>246</pageFirst>
    <pageLast>259</pageLast>
    <pageNumber/>
    <edition/>
    <issue>2</issue>
    <volume>9</volume>
    <type>articler</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2019-02-12</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Recovery of Li(Ni0.33Mn0.33Co0.33)O2 from Lithium-Ion Battery Cathodes: Aspects of Degradation</title>
    <abstract language="eng">Nickel–manganese–cobalt oxides, with LiNi0.33Mn0.33Co0.33O2 (NMC) as the most prominent compound, are state-of-the-art cathode materials for lithium-ion batteries in electric vehicles. The growing market for electro mobility has led to a growing global demand for Li, Co, Ni, and Mn, making spent lithium-ion batteries a valuable secondary resource. Going forward, energy- and resource-inefficient pyrometallurgical and hydrometallurgical recycling strategies must be avoided. We presented an approach to recover NMC particles from spent lithium-ion battery cathodes while preserving their chemical and morphological properties, with a minimal use of chemicals. The key task was the separation of the cathode coating layer consisting of NMC, an organic binder, and carbon black, from the Al substrate foil. This can be performed in water under strong agitation to support the slow detachment process. However, the contact of the NMC cathode with water leads to a release of Li+ ions and a fast increase in the pH. Unwanted side reactions may occur as the Al substrate foil starts to dissolve and Al(OH)3 precipitates on the NMC. These side reactions are avoided using pH-adjusted solutions with sufficiently high buffer capacities to separate the coating layer from the Al substrate, without precipitations and without degradation of the NMC particles.</abstract>
    <parentTitle language="eng">Nanomaterials</parentTitle>
    <identifier type="doi">10.3390/nano9020246</identifier>
    <identifier type="url">https://www.mdpi.com/journal/nanomaterials/special_issues/charact_nano</identifier>
    <identifier type="url">https://www.mdpi.com/2079-4991/9/2/246</identifier>
    <identifier type="issn">2079-4991</identifier>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">false</enrichment>
    <author>
      <firstName>Tim</firstName>
      <lastName>Sieber</lastName>
    </author>
    <submitter>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </submitter>
    <author>
      <firstName>Jana</firstName>
      <lastName>Ducke</lastName>
    </author>
    <author>
      <firstName>Anja</firstName>
      <lastName>Rietig</lastName>
    </author>
    <author>
      <firstName>Thomas</firstName>
      <lastName>Langner</lastName>
    </author>
    <author>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>lithium</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>nickel–manganese–cobalt oxide</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NMC</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>leaching</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>recycling</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>SEM-EDX</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Raman spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>lithium ion battery</value>
    </subject>
    <collection role="institutes" number="2206">FG Physikalische Chemie</collection>
  </doc>
  <doc>
    <id>24319</id>
    <completedYear/>
    <publishedYear>2019</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber>7</pageNumber>
    <edition/>
    <issue/>
    <volume>126</volume>
    <type>articler</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2019-08-21</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Measurement of the temperature dependence of lattice deformations in silicon using Raman microscopy</title>
    <abstract language="eng">The effect of heating and cooling in the range of 25–900 °C on the lattice deformations of diamond wire-sawn polycrystalline and scratched monocrystalline silicon surfaces was studied in detail using Raman microscopy. Mechanically treated silicon surfaces contain tensile or compressive strained silicon with varying deformation strength and areas with high-pressure silicon phases and amorphous silicon. It is shown that compressive deformed silicon relaxes after heating the sample to 600 °C, while tensile deformed silicon only relaxes after multiple heating and cooling cycles. Raman measurements during the heating and after the cooling phases reveal the individual thermal expansion and relaxation behavior of the deformed silicon states. Compressive deformed silicon relaxes during the heating phase, while tensile deformed silicon relaxes during the cooling phase. It is, therefore, possible to separately relax certain deformation states using thermal annealing without changing the topography of the surface.</abstract>
    <parentTitle language="eng">Journal of Applied Physics</parentTitle>
    <identifier type="doi">10.1063/1.5090476</identifier>
    <identifier type="url">https://aip.scitation.org/doi/10.1063/1.5090476</identifier>
    <identifier type="issn">1089-7550</identifier>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <enrichment key="Artikelnummer">035103</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">false</enrichment>
    <author>
      <firstName>Steven</firstName>
      <lastName>Herold</lastName>
    </author>
    <submitter>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </submitter>
    <author>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Raman spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>mechanical stress</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>silicon</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>crystallization</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>relaxation</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>thermal treatment</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>solar cell</value>
    </subject>
    <collection role="institutes" number="2206">FG Physikalische Chemie</collection>
  </doc>
  <doc>
    <id>24478</id>
    <completedYear/>
    <publishedYear>2019</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>22002</pageFirst>
    <pageLast>22013</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>21</volume>
    <type>articler</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2019-10-11</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">A revised model of silicon oxidation during the dissolution of silicon in HF/HNO₃ mixtures</title>
    <abstract language="eng">The stoichiometry of wet chemical etching of silicon in concentrated HF/HNO₃ mixtures was investigated. The formation of nitrogen species enriched in the etching mixture and their reactivity during the etching process was studied. The main focus of the investigations was the comprehensive quantification of the gaseous reaction products using mass spectrometry. Whereas previously it could only be speculated that nitrogen was a product, its formation was detected for the first time. The formation of hydrogen, N₂, N₂O and NH₄⁺ showed a dependence on the etching bath volume used, which indicates the formation of nitrogen compounds by side reactions. Simultaneously, the ratio of the nitrogen oxides, NO and NO₂, formed decreases with increasing etching bath volume, while nitric acid consumption increases, so that the formation of NO₂ could also be identified as a side reaction. Based on the stoichiometries obtained, a new reaction scheme for the reduction of nitric acid during etching in HF/HNO₃ mixtures and an electron balance for the oxidation of silicon is presented.</abstract>
    <parentTitle language="eng">Physical chemistry, chemical physics</parentTitle>
    <identifier type="doi">10.1039/c9cp04429a</identifier>
    <identifier type="url">https://pubs.rsc.org/en/content/articlelanding/2019/CP/C9CP04429A#!divAbstract</identifier>
    <identifier type="issn">1463-9076</identifier>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">false</enrichment>
    <author>
      <firstName>Anja</firstName>
      <lastName>Rietig</lastName>
    </author>
    <submitter>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </submitter>
    <author>
      <firstName>Thomas</firstName>
      <lastName>Langner</lastName>
    </author>
    <author>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>silicon</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>etching</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>mechanism</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>nitrogen oxide</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>hydrogen</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>mass spectrometry</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Raman spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>kinetics</value>
    </subject>
    <collection role="institutes" number="2206">FG Physikalische Chemie</collection>
  </doc>
  <doc>
    <id>24481</id>
    <completedYear/>
    <publishedYear>2019</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>28</pageFirst>
    <pageLast/>
    <pageNumber/>
    <edition>1. Auflage</edition>
    <issue/>
    <volume/>
    <type>conferenceobject_noref</type>
    <publisherName>Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg</publisherName>
    <publisherPlace>Ulm</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2019-10-11</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Degradation effects on Li(Ni0.33Mn0.33Co0.33)O2 in the recovery of lithium battery cathodes</title>
    <abstract language="eng">The compound Li(Ni0.33Mn0.33Co0.33)O2 (NMC) is the state-of-the-art lithium-ion battery cathode material. Due to the increasing demand NMC is of crucial economically importance for the worldwide emerging market of electromobility. Recycling of end-of-life lithium-ion batteries to recover NMC, in particular of batteries from automotive vehicles, is one future strategy to save costs and to become more independent from the supply of the essential elements Co and Mn. Several concepts for NMC recycling from lithium-ion batteries are based on wet-chemical process steps, in particular, to separate the NMC containing cathode layer from the underlying metal foil. However, NMC is very sensitive against the attack by water and reagents that are added to promote the separation process.&#13;
The present study deals with the wet-chemical recycling of NMC using aqueous reagent solutions in a under varying process conditions. The recovered NMC samples are characterized in order to study the ongoing degradation at the surface of the NMC particles. In particular, two major degradation pathways are identified: (i) a preferential loss of lithium and nickel and (ii) the formation of passivation layers due to unwanted side reactions. DRIFT measurements are performed to study the NMC surface species after the recovery processes. SEM/EDX mappings are used to detect changes in the chemical composition in the surface region of the chemically treated NMC particles. Finally, a detailed study of the changes in the chemical state at the NMC particle surface is done by Raman microscopy by means of the deconvolution of the recorded spectra into their A1G component (representing the metal-oxide phonons) and into the Eg component (representing the oxide-metal-oxide phonons). &#13;
As result of this study, the consequences of different wet-chemical process conditions on the quality of the recovered NMC material are discussed.</abstract>
    <parentTitle language="eng">Advanced Lithium Batteries for Automobile Applications - ABAA 12, Book of Abstracts</parentTitle>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">false</enrichment>
    <author>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </author>
    <submitter>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </submitter>
    <author>
      <firstName>Tim</firstName>
      <lastName>Sieber</lastName>
    </author>
    <author>
      <firstName>Jana</firstName>
      <lastName>Ducke</lastName>
    </author>
    <author>
      <firstName>Thomas</firstName>
      <lastName>Langner</lastName>
    </author>
    <author>
      <firstName>Anja</firstName>
      <lastName>Rietig</lastName>
    </author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>lithium ion battery</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>recycling</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NMC</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>electromobility</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>degradation</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Raman spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>cathode</value>
    </subject>
    <collection role="institutes" number="2206">FG Physikalische Chemie</collection>
  </doc>
  <doc>
    <id>25307</id>
    <completedYear/>
    <publishedYear>2020</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>366</pageFirst>
    <pageLast>372</pageLast>
    <pageNumber/>
    <edition/>
    <issue>2</issue>
    <volume>51</volume>
    <type>articler</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2020-02-25</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Raman spectroscopic determination of the degree of dissociation of nitric acid in binary and ternary mixtures with HF and H2SiF6</title>
    <abstract language="eng">The oxidizing effect of nitric acid in aqueous solutions depends on the concentration of undissociated nitric acid. This makes the concentration of undissociated nitric acid an essential parameter to monitor and control the quality of silicon etching in the industrial manufacturing of solar cells. In the present study, a method known already is extended in such a way that the degree of dissociation of nitric acid can be determined by Raman spectroscopy in HF/HNO3/H2SiF6 acid mixtures over a broad concentration range for the first time and without using an internal or external standard to compensate the typical time‐dependent drift of a Raman spectrometer. The method developed requires the calculation of a peak area ratio from the areas of the unimpeded Raman signals assigned to nitrate (νN − O) at 1,048 cm−1 and to undissociated HNO3 (νN − OH) at 957 cm−1. The correlation between the peak ratio and the degree of dissociation of nitric acid revealed can be described by a simple empirical equation. Using this equation, the degree of dissociation of nitric acid can be determined over a broad concentration range in binary and ternary mixtures of HNO3 with HF and H2SiF6. The impact of the acids HF and H2SiF6 and the total water content in the degree of dissociation of nitric acid is discussed.</abstract>
    <parentTitle language="eng">Journal of Raman Spectroscopy</parentTitle>
    <identifier type="doi">10.1002/jrs.5769</identifier>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <enrichment key="Fprofil">1 Energiewende und Dekarbonisierung / Energy Transition and Decarbonisation</enrichment>
    <author>
      <firstName>Thomas</firstName>
      <lastName>Langner</lastName>
    </author>
    <submitter>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </submitter>
    <author>
      <firstName>Anja</firstName>
      <lastName>Rietig</lastName>
    </author>
    <author>
      <firstName>Jörg</firstName>
      <lastName>Acker</lastName>
    </author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Raman spectroscopy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>nitric acid</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>dissociation</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>hexafluosilicic acid</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>hydrofluoric acid</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>silicon</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>etching</value>
    </subject>
    <collection role="institutes" number="2206">FG Physikalische Chemie</collection>
  </doc>
</export-example>
