Volcanic Eruption in the Nanoworld: Efficient Oxygen Exchange at the Si/SnO2 Interface

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-08, Vol.20 (35), p.e2404508-n/a
• Main Authors: Liu, Poting, Makarova, Anna, Freiberg, Katharina, Grinter, David C., Sharma, Divanshu, Ferrer, Pilar, Chuvenkova, Olga, Deckert‐Gaudig, Tanja, Turishchev, Sergey, Lippmann, Stephanie, Sivakov, Vladimir
• Format: Article
• Language: English
• Subjects: Amorphous silicon; Chemical vapor deposition; Magma; Nanostructure; Oxygen; Particulate composites; Photoelectrons; silicon; Silicon dioxide; Silicon oxides; synchrotron; Synchrotron radiation; Thermal energy; thermodynamic; Tin dioxide; tin oxides; Volcanic activity; Volcanic eruptions; volcano
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202404508

Here, a phenomenon of efficient oxygen exchange between a silicon surface and a thin layer of tin dioxide during chemical vapor deposition is presented, which leads to a unique Sn:SiO2 layer. Under thermodynamic conditions in the temperature range of 725–735 °C, the formation of nanostructures with volcano‐like shapes in “active” and “dormant” states are observed. Extensive characterization techniques, such as electron microscopy, X‐ray diffraction, synchrotron radiation‐based X‐ray photoelectron, and X‐ray absorption near‐edge structure spectroscopy, are applied to study the formation. The mechanism is related to the oxygen retraction between tin(IV) oxide and silicon surface, leading to the thermodynamically unstable tin(II)oxide, which is immediately disproportionate to metallic Sn and SnO2 localized in the SiO2 matrix. The diffusion of metallic tin in the amorphous silicon oxide matrix leads to larger agglomerates of nanoparticles, which is similar to the formation of a magma chamber during the natural volcanic processes followed by magma eruption, which here is associated with the formation of depressions on the surface filled with metallic tin particles. This new effect contributes a new approach to the formation of functional composites but also inspires the development of unique Sn:SiO2 nanostructures for diverse application scenarios, such as thermal energy storage. The link between the macro‐ and nanoworld is related to the observed unique phenomenon, resembling a natural volcanic process, due to the thermodynamic instability of the system occurring at the nanoscale during the growth of thin layers of SnO2 on Si. The mechanism of efficient oxygen exchange between SnO2 and the Si surface at the nanoscale is studied for the first time.