Structural, optical, and electrical properties of Hf-doped ZnO films deposited by atomic layer deposition

Hafnium-doped zinc oxide (HZO) films were deposited by atomic layer deposition at 220 °C. The influences of Hf content on the structure, optical and electrical properties of HZO films were investigated systematically. The X-ray diffraction spectra revealed that the grown HZO films have a hexagonal structure with the preferential orientation changing from a-axis to c-axis with increasing Hf-doping concentrations. The X-ray photoelectron spectra showed the HZO films contain oxygen vacancies and Zn interstitials. Based on photoluminescence measurements, the dominating ultraviolet emission peak exhibited a blue-shift and its intensity was found to decrease with the increasing of Hf-doping content. In addition, a minimum resistivity of 1.6 × 10− 3 Ωcm was obtained for the HZO film with 4.6 at.% Hf.