Oxygen-Deficiency-Driven Phase Segregation Enables Enhanced Hole Transport in Amorphous Tellurium Oxides

High Resolution Image Download MS PowerPoint Slide Amorphous oxide semiconductors allow scalable electronics, yet high-mobility p-type counterparts remain rare because O-2 p valence bands are typically deep and spatially localized. Motivated by recent reports of unusually high hole mobilities in Se-doped oxygen-deficient amorphous tellurium oxides ( a -TeO x ), we investigated a -TeO x with and without Se doping using machine-learning-accelerated ab initio molecular dynamics with hybrid-functional defect calculations. We find that oxygen depletion drives nanoscale segregation into interpenetrating a -Te and a -TeO 2 domains with distinct roles: Te vacancies in oxide-like/interfacial environments supply holes, while transport is mediated by percolating Te-5 p pathways within the a -Te subnetwork. Upon doping, we theoretically verify that Se preferentially incorporates into the a -Te domains enhancing connectivity. This preference is nontrivial without explicit modeling given that Se shares similar electronic structures with both Te and O. We further find that reducing the oxygen content can likewise enhance hole conductivity. Finally, using amorphous SeO x, we show that domain segregation persists in other amorphous chalcogen oxides, suggesting a transferable route to achieving higher-mobility p-type amorphous oxides.