Distinctive Electric Properties of Group 14 Oxides: SiO2, SiO, and SnO2

Int J Mol Sci. 2023 Nov 5;24(21):15985. doi: 10.3390/ijms242115985.

Abstract

The oxides of group 14 have been widely used in numerous applications in glass, ceramics, optics, pharmaceuticals, and food industries and semiconductors, photovoltaics, thermoelectrics, sensors, and energy storage, namely, batteries. Herein, we simulate and experimentally determine by scanning kelvin probe (SKP) the work functions of three oxides, SiO2, SiO, and SnO2, which were found to be very similar. Electrical properties such as electronic band structure, electron localization function, and carrier mobility were also simulated for the three crystalline oxides, amorphous SiO, and surfaces. The most exciting results were obtained for SiO and seem to show Poole-Frankel emissions or trap-assisted tunneling and propagation of surface plasmon polariton (SPP) with nucleation of solitons on the surface of the Aluminum. These phenomena and proposed models may also describe other oxide-metal heterojunctions and plasmonic and metamaterials devices. The SiO2 was demonstrated to be a stable insulator interacting less with the metals composing the cell than SnO2 and much less than SiO, configuring a typical Cu/SiO2/Al cell potential well. Its surface charge carrier mobility is small, as expected for an insulator. The highest charge carrier mobility at the lowest conduction band energy is the SnO2's and the most symmetrical the SiO's with a similar number of electron holes at the conduction and valence bands, respectively. The SnO2 shows it may perform as an n-type semiconductor.

Keywords: ab initio simulations; charge carrier mobilities; electronic band structure; oxides group 14; scanning kelvin probe; silica; silicon monoxide; tin dioxide; work functions.

MeSH terms

  • Aluminum
  • Glass / chemistry
  • Metals / chemistry
  • Oxides* / chemistry
  • Silicon Dioxide* / chemistry

Substances

  • Oxides
  • Silicon Dioxide
  • Metals
  • Aluminum

Grants and funding

This work was funded by the Portuguese Foundation for Science and Technology FCT UIDP/50022/2020 Emerging Technologies–LAETA, and the University of Porto—Galp IJUP project: “Electrifying the future with wireless technologies: electrode less enabled by ferroelectrics”. This work is also a result of Agenda CVB—Cadeia de Valor das Baterias em Portugal, nr. C644864613-00000003, financed by the Recovery and Resilience Plan (PRR) and by European Union—NextGeneration EU and of Agenda NGS—New Generation Storage, nr. C644936001-00000045, investment project nr. 58, financed by the Recovery and Resilience Plan (PRR) and the European Union—NextGeneration EU.