Bonan Zhu1,David Scanlon1
University College London1
Bonan Zhu1,David Scanlon1
University College London1
Transparent conducting oxides (TCOs), combing two seeming mutually exclusive properties, are essential components for a range of optoelectronic applications. Existing materials such as indium-doped tin oxides (ITOs) require raw materials that are limited in supply (e.g., In). Hence, cost-effective alternatives are in urgent need<sup>1</sup>. Having the same rutile lattice, AlSbO<sub>4 </sub>can be seen as a cation mutated version of SnO<sub>2</sub> with Sn (IV) replaced Al (III) and Sb (V). Sb based systems are interesting as Sb (V) is isoelectronic to Sn(IV) and In (III) which are known to yield strongly dispersive conduction bands<sup>2</sup>. In this work, a thorough computational investigation is conducted to assess the potential of AlSbO<sub>4</sub> as a TCO. Despite the early experimental report of a fully cation-disordered structure<sup>3</sup>, Monte-Carlo simulations based on cluster expansions show a relatively high order-disorder transition temperature of about 1800 K. The 0 K ground state structure is also obtained and found to contain a wide direct band gap of ~4 eV, and an electron effective mass of 0.38 m<sub>e </sub>at the conduction band minimum. Band alignment calculations suggest a large electron affinity and ionisation potential, which can be attributed to the strong overlap between Sb 2s and O 2p states, making it a potential contact material. The dopability of this system will also be discussed. Beyond potential TCO applications, a low lattice thermal conductivity is found with the ordered ground state structure, and the possibility of further reduction in conductivity through disordering makes it a potential candidate material for thermal barrier coating.<br/><br/><br/>(1) Ellmer, K. Past Achievements and Future Challenges in the Development of Optically Transparent Electrodes. <i>Nature Photon</i> <b>2012</b>, <i>6</i> (12), 809–817. https://doi.org/10.1038/nphoton.2012.282.<br/>(2) Jackson, A. J.; Parrett, B. J.; Willis, J.; Ganose, A. M.; Leung, W. W. W.; Williamson, B. A. D.; Liu, Y.; Kim, T. K.; Hoesch, M.; Ishibe-Veiga, L.; Kalra, R.; Neu, J.; Schmuttenmaer, C. A.; Lee, T.-L.; Regoutz, A.; Veal, T. D.; Palgrave, R. G.; Perry, R.; Scanlon, D. O. Computational Prediction and Experimental Realisation of Earth Abundant Transparent Conducting Oxide Ga-Doped ZnSb2O6. <b>2022</b>. https://doi.org/10.26434/chemrxiv-2022-mz5dc.<br/>(3) Donaldson, J. D.; Kjekshus, A.; Nicholson, D. G.; Rakke, T.; Skoglund, U. Properties of Sb-Compounds with Rutile-like Structures. <i>Acta Chem. Scand.</i> <b>1975</b>, <i>29a</i>, 803–809. https://doi.org/10.3891/acta.chem.scand.29a-0803.