Bilayer BaSnO₃ thin film transistors on silicon substrates

Barium tin oxide BaSnO₃ (BSO) is a novel wide-bandgap semiconducting material with high electron mobility and is considered as a promising alternative to indium-containing amorphous oxide semiconductors. Herein, high-performance BSO thin film transistors (TFTs) on non-epitaxial substrates by forming a unique bilayer structure via sputtering are demonstrated. Synergistic control over the deposition rate and post-annealing temperatures result in precise formation and modulation of oxygen vacancies, culminating in insulating and semiconducting BaSnO₃ fractions within the bilayer structure. These devices exhibit thermally activated charge transport properties with a field effect mobility of 0.75 cm² V^-1 s^-1 and an I_on/I_off ratio of 10⁴. These novel BSO TFT devices are stable for at least 20 days with moderate storage conditions (room temperature, 30-40% humidity, air conditions), thus paving the way for the facile fabrication of high-performance indium-free switching devices.