氧气
氢
间质缺损
掺杂剂
化学物理
化学
分子
水蒸气
氢键
密度泛函理论
结合能
结晶学
兴奋剂
物理化学
材料科学
无机化学
计算化学
原子物理学
有机化学
物理
光电子学
作者
Amit Samanta,Joel B. Varley,Vincenzo Lordi
摘要
Using hybrid functional-based density functional theory calculations, we analyze the structure and kinetics of defects formed in two competing synthesis routes to prepare hydrogen-doped In2O3 films, using a hydrogen and oxygen gas mixture vs synthesis in the presence of water vapor. For both of these synthesis routes, we find that H+ is the dominant defect species: when the Fermi level is close to the conduction band, H+ has a lower formation energy than other intrinsic or extrinsic defects. Our results also suggest that water molecules spontaneously split into H+ (which occupies octahedral voids) and OH− interstitials (which occupies vacant oxygen lattice sites or oxygen vacancies). From the analysis of the binding energies between these different defects, we conclude that these defects do not cluster and are most likely to stay spatially distributed throughout the films. In addition, the sum of formation energies of an oxygen (i.e., Oi2−) and a H+ interstitial is close to the formation energy of a OH− interstitial, meaning that water molecules are completely split into 2H+ and Oi2− at the synthesis conditions. Further, in the presence of H2 + O2 gas mixture, oxygen interstitials occupy oxygen vacancies while hydrogen interstitials occupy vacant oxygen lattice sites and form bonds with lattice oxygens. Our analysis of the defect equilibria suggests that the hydrogen content in films synthesized in the presence of water vapor is higher than films synthesized in the presence of a hydrogen gas mixture. At high dopant concentrations, a hydrogen bond network is formed in the system and this leads to large distortions in the lattice.
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