Ivan Isakov1, Hendrik Faber2, Alexander D. Mottram1, Satyajit Das1, Max Grell1, Anna Regoutz3, Rebecca Kilmurray4, Martyn A. McLachlan4, David J. Payne4, Thomas D. Anthopoulos1,2
1Department of Physics and Centre for Plastic Electronics, Blackett Laboratory, Imperial College London, London SW7 2BW, UK
2King Abdullah University of Science and Technology (KAUST) KAUST Solar Center and Physical Science and Engineering Division (PSE) Thuwal 23955–6900 Saudi Arabia
3Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
4Department of Materials, Royal School of Mines, Imperial College London, London SW7 2AZ, UK
Tóm tắt
AbstractThe dependence of charge carrier mobility on semiconductor channel thickness in field‐effect transistors is a universal phenomenon that has been studied extensively for various families of materials. Surprisingly, analogous studies involving metal oxide semiconductors are relatively scarce. Here, spray‐deposited In2O3 layers are employed as the model semiconductor system to study the impact of layer thickness on quantum confinement and electron transport along the transistor channel. The results reveal an exponential increase of the in‐plane electron mobility (µe) with increasing In2O3 thickness up to ≈10 nm, beyond which it plateaus at a maximum value of ≈35 cm2 V−1 s−1. Optical spectroscopy measurements performed on In2O3 layers reveal the emergence of quantum confinement for thickness <10 nm, which coincides with the thickness that µe starts deteriorating. By combining two‐ and four‐probe field‐effect mobility measurements with high‐resolution atomic force microscopy, it is shown that the reduction in µe is attributed primarily to surface scattering. The study provides important guidelines for the design of next generation metal oxide thin‐film transistors.
