Effects of cold atmospheric plasma pretreatment of glass substrates on the properties of CdO films deposited by DC pulsed magnetron sputtering
摘要
This work explores the effect of atmospheric pressure plasma (APP) pretreatment on the growth behavior and functional characteristics of CdO thin films deposited on glass substrates using DC pulsed magnetron sputtering. Prior to deposition, the substrates were exposed to plasma for durations ranging from 5 to 20 s in order to modify their surface condition. The treatment significantly altered the wettability of the glass surface, reducing the contact angle from approximately 35° to nearly 0°, which promotes more favorable conditions for film growth and leads to an increase in thickness from about 120 to 150 nm. Infrared analysis indicates the presence of surface-related vibrational features that can be associated with plasma-induced modifications. Such changes reflect an enhanced level of surface activation, which may play a role in influencing the subsequent film formation process. The estimated optical bandgap values for the untreated and APP-treated films ranged from 2.73 to 2.83 eV, indicating that plasma pretreatment induces only subtle modifications in the electronic structure. In parallel, variations in refractive index and extinction coefficient suggest modifications in the optical response of the material. Electrical measurements showed a notable decrease in resistivity from 18.0 × 10−3 Ω·cm to 11 × 10−4 Ω·cm after 20 s of plasma exposure, resulting in an improved figure of merit of 1.4 × 10−4 Ω−1. Overall, the findings demonstrate that APP pretreatment provides an effective route for controlling the structural and functional properties of CdO thin films, making it a promising approach for applications in transparent conducting oxides.