Tuning Atomic Diffusion and Carrier Concentration in ITO Films via In-Situ Resistance Monitoring

We present a study on tuning atomic diffusion and carrier concentration in Sn-doped In₂O₃ (ITO) films using an in-situ resistance monitoring approach during post-annealing. By varying the annealing ramping rate and gas atmosphere, we decouple the effects of thermal kinetics and chemical environment on the crystallization behavior and electronic properties of amorphous ITO films. Our results reveal that crystallization and densification temperatures are predominantly governed by the ramping rate, while carrier concentration is strongly modulated by the gas atmosphere. Notably, the ITO film annealed in forming gas at low ramping rates exhibits enhanced conductivity and optical transmittance due to the oxygen vacancy-induced electron doping, as confirmed by hard X-ray photoelectron spectroscopy. Activation energies of the atomic diffusion in amorphous ITO films were quantified as 1.07 eV and 0.99 eV for crystallization and densification, respectively. Our findings introduce a robust, in-situ resistance monitoring strategy for precise control of structural and electronic properties in transparent conducting oxides, offering a scalable methodology for advanced optoelectronic device fabrication.