IMPACT OF THERMAL TREATMENT ON THE STRUCTURE AND PROPERTIES OF COPPER OXIDE THIN FILMS DEPOSITED BY ATMOSPHERIC PRESSURE SPATIAL ATOMIC LAYER DEPOSITION

Abstract

CuO_x holds significant potential in various fields including energy conversion and storage, gas sensors, and catalysis. In this work, we present our study on the atomic layer deposited CuO thin films using Cu(II) acetylacetonate and ozone in ambient conditions, as well as the impact of thermal treatment in different conditions on the film properties. As a result, CuO thin films were successfully grown on quartz and SiO₂/Si substrate at 275 °C with a growth rate of 0.049 nm/cycle. The thermal annealing in ambient conditions at 600 °C helps to improve the crystallinity of CuO, while the as-deposited monoclinic CuO phase can be converted into the cuprous Cu₂O phase via annealing in the N₂ atmosphere. Via Hall effect measurement, we demonstrated p-type semiconducting characteristics of the Cu₂O thin film with carrier mobility μ = 9.1 ×10^-3 [cm²V^-1s^-1], and carrier density p = 4.46 ×10¹⁸ [cm^-3]. Additionally, the transmittance of the Cu₂O films increased by 10–20% compared to the as-deposited CuO film. These findings suggest that Cu₂O is a promising material for the hole transport layer in thin-film solar cells, while CuO can be suitable for the absorber layer in photovoltaic devices.