CVD Grown Tungsten Oxide for Low Temperature Hydrogen Sensing: Tuning Surface Characteristics via Materials Processing for Sensing Applications

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Martin Wilken - , Ruhr University Bochum (Author)
  • Engin Ciftyürek - , Heinrich Heine University Düsseldorf (Author)
  • Stefan Cwik - , Ruhr University Bochum (Author)
  • Lukas Mai - , Ruhr University Bochum (Author)
  • Bert Mallick - , Ruhr University Bochum (Author)
  • Detlef Rogalla - , Ruhr University Bochum (Author)
  • Klaus Schierbaum - , Heinrich Heine University Düsseldorf (Author)
  • Anjana Devi - , Ruhr University Bochum (Author)

Abstract

The intrinsic properties of semiconducting oxides having nanostructured morphology are highly appealing for gas sensing. In this study, the fabrication of nanostructured WO3 thin films with promising surface characteristics for hydrogen (H2) gas sensing applications is accomplished. This is enabled by developing a chemical vapor deposition (CVD) process employing a new and volatile tungsten precursor bis(diisopropylamido)-bis(tert-butylimido)-tungsten(VI), [W(NtBu)2(NiPr2)2]. The as-grown nanostructured WO3 layers are thoroughly analyzed. Particular attention is paid to stoichiometry, surface characteristics, and morphology, all of which strongly influence the gas-sensing potential of WO3. Synchrotron-based ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), X-ray photoelectron emission microscopy (XPEEM), low-energy electron microscopy (LEEM) and 4-point van der Pauw (vdP) technique made it possible to analyze the surface chemistry and structural uniformity with a spatially resolved insight into the chemical, electronic and electrical properties. The WO3 layer is employed as a hydrogen (H2) sensor within interdigitated mini-mobile sensor architecture capable of working using a standard computer's 5 V 1-wirebus connection. The sensor shows remarkable sensitivity toward H2. The high, robust, and repeatable sensor response (S) is attributed to the homogenous distribution of the W5+ oxidation state and associated oxygen vacancies, as shown by synchrotron-based UPS, XPS, and XPEEM analysis.

Details

Original languageEnglish
Article number2204636
Number of pages13
JournalSmall
Volume19
Issue number1
Early online date10 Nov 2022
Publication statusPublished - Jan 2023
Peer-reviewedYes
Externally publishedYes

External IDs

PubMed 36354167

Keywords

Keywords

  • hydrogen sensing, metalorganic chemical vapor deposition (MOCVD), nanostructured layers, surface characteristics, tungsten oxides