Indium Tin Oxide (ITO) thin films have been extensively studied for their excellent photoelectric performance. Nevertheless, the diffusion mechanism of doped-tin in ITO thin film is not sufficiently illuminated to date. Herein, the diffusion behaviors of Sn dopant in ITO films fabricated by RF-sputtering were investigated. As-deposited ITO thin films were treated by supercritical CO₂ (SCCO₂) fluid with aqua ammonia, then they were annealed at different temperatures. X-ray diffraction patterns (XRD) showed that the crystallization of ITO films occurred upon annealing above 300 °C, which resulted in the higher mobility of electron carriers. Relatively lower electron carrier concentrations were found for the ITO films after SCCO₂ treatment and successive annealing at temperatures of 500 and 600 °C. X-ray photoelectron spectroscopy (XPS) analysis revealed that the content of tin element near the surface of ITO thin films can be reduced by SCCO₂ fluid treatment. Subsequently, the annealing process results in the diffusion of the tin element to the sub-surface region of the films at different levels depending on the annealing temperature. The present work provides direct evidence for bleaching of tin dopant in the sub-surface region of ITO films by SCCO₂ treatments and diffusion of tin from deeper regions to the sub-surface region of the ITO films upon annealing.

铟锡氧化物 (ITO) 薄膜因其优异的光电性能而被广泛研究。然而，迄今为止，ITO薄膜中掺杂锡的扩散机制还没有得到充分阐明。在此，研究了 Sn 掺杂剂在射频溅射制备的 ITO 薄膜中的扩散行为。沉积的 ITO 薄膜用超临界 CO ₂ (SCCO ₂ ) 流体和氨水处理，然后在不同温度下退火。X 射线衍射图 (XRD) 表明 ITO 薄膜在 300 ℃以上退火时发生结晶，这导致电子载流子的迁移率更高。_{SCCO 2}后 ITO 薄膜的电子载流子浓度相对较低在 500 和 600 °C 的温度下处理和连续退火。_{X射线光电子能谱(XPS)分析表明，通过SCCO 2}流体处理可以降低ITO薄膜表面附近的锡元素含量。随后，退火过程导致锡元素根据退火温度以不同水平扩散到薄膜的亚表面区域。目前的工作为通过 SCCO ₂处理漂白 ITO 薄膜亚表面区域中的锡掺杂剂以及在退火时锡从较深区域扩散到 ITO 薄膜的亚表面区域提供了直接证据。