biostudies-literatureDoiron BDeutsche ForschungsgemeinschaftEuropean Research CouncilSolar Technologies go HybridCentre for Nano and Soft Matter SciencesEngineering and Physical Sciences Research CouncilThomas Young Centre30417-30426https://www.ebi.ac.uk/biostudies/studies/S-EPMC10316319biostudies-literatureUnknown15(25)Understanding metal-semiconductor interfaces is critical to the advancement of photocatalysis and sub-bandgap solar energy harvesting where electrons in the metal can be excited by sub-bandgap photons and extracted into the semiconductor. In this work, we compare the electron extraction efficiency across Au/TiO₂ and titanium oxynitride (TiON)/TiO_2-<i>x</i> interfaces, where in the latter case the spontaneously forming oxide layer (TiO_2-<i>x</i>) creates a metal-semiconductor contact. Time-resolved pump-probe spectroscopy is used to study the electron recombination rates in both cases. Unlike the nanosecond recombination lifetimes in Au/TiO₂, we find a bottleneck in the electron relaxation in the TiON system, which we explain using a trap-mediated recombination model. Using this model, we investigate the tunability of the relaxation dynamics with oxygen content in the parent film. The optimized film (TiO_0.5N_0.5) exhibits the highest carrier extraction efficiency (<i>N</i>_FC ≈ 2.8 × 10¹⁹ m^-3), slowest trapping, and an appreciable hot electron population reaching the surface oxide (<i>N</i>_HE ≈ 1.6 × 10¹⁸ m^-3). Our results demonstrate the productive role oxygen can play in enhancing electron harvesting and prolonging electron lifetimes, providing an optimized metal-semiconductor interface using only the native oxide of titanium oxynitride.ACS applied materials & interfacesOptimizing Hot Electron Harvesting at Planar Metal-Semiconductor Interfaces with Titanium Oxynitride Thin Films.PMC10316319EP/V001914/1EP/L015277/1TYC-101EP/W012197/1EP/W017075/1EP/M013812/1EP/N005244/1EXC 2089/1 390776260802989EP/R00661X/1EP/L000202Alford NMMihai ABower RCohen LFPetrov PFearn SMaier SALischner JOulton RFHuttenhofer LLi YDal Forno SCortes EDoiron BfalseOptimizing Hot Electron Harvesting at Planar Metal-Semiconductor Interfaces with Titanium Oxynitride Thin Films.Understanding metal-semiconductor interfaces is critical to the advancement of photocatalysis and sub-bandgap solar energy harvesting where electrons in the metal can be excited by sub-bandgap photons and extracted into the semiconductor. In this work, we compare the electron extraction efficiency across Au/TiO₂ and titanium oxynitride (TiON)/TiO_2-<i>x</i> interfaces, where in the latter case the spontaneously forming oxide layer (TiO_2-<i>x</i>) creates a metal-semiconductor contact. Time-resolved pump-probe spectroscopy is used to study the electron recombination rates in both cases. Unlike the nanosecond recombination lifetimes in Au/TiO₂, we find a bottleneck in the electron relaxation in the TiON system, which we explain using a trap-mediated recombination model. Using this model, we investigate the tunability of the relaxation dynamics with oxygen content in the parent film. The optimized film (TiO_0.5N_0.5) exhibits the highest carrier extraction efficiency (<i>N</i>_FC ≈ 2.8 × 10¹⁹ m^-3), slowest trapping, and an appreciable hot electron population reaching the surface oxide (<i>N</i>_HE ≈ 1.6 × 10¹⁸ m^-3). Our results demonstrate the productive role oxygen can play in enhancing electron harvesting and prolonging electron lifetimes, providing an optimized metal-semiconductor interface using only the native oxide of titanium oxynitride.2023-01-01T00:00:00Z2023 Jun2025-04-04T14:08:31.43Z2025-04-04T14:08:31.43ZS-EPMC103163193730741010.1021/acsami.3c02812