Carrier-mediated reduction mechanism in WO3 nanowires under electron-beam irradiation

Electron-beam irradiation often induces unintended structural and chemical changes in materials. Here, we show that damage and reduction in tungsten trioxide (WO3) nanowires are primarily driven by a carrier-mediated ionization process. In situ electron microscopy and electron energy-loss spectroscopy reveal structural degradation accompanied by the reduction of W6+ to W5+, while carrier dynamics simulations identify persistent, high-density electron-hole populations. Quantitative analyses and control experiments indicate that knock-on displacement and heating contribute minimally. This study establishes a microscopy-based quantitative framework for understanding electron-beam-induced damage and redox processes, highlighting the potential of electron microscopy for mechanistic insights and nanoscale chemical patterning in oxides.