Substrate-engineered microstructural evolution and nitric oxide sensing performance of ZnO nanofilms deposited by RF magnetron sputtering
Vacuum, cilt.254, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 254
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.vacuum.2026.115746
- Dergi Adı: Vacuum
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Depletion layer modulation, NO sensing, RF magnetron sputtering, Substrate film interaction, ZnO
- Gazi Üniversitesi Adresli: Evet
Özet
Understanding and controlling substrate–film interactions is essential for optimizing metal-oxide gas sensors, yet this factor is often overlooked compared with doping or surface functionalization. Here, we systematically investigate substrate-dependent microstructural evolution and NO sensing behavior of ZnO thin films deposited by RF magnetron sputtering under controlled vacuum conditions. ZnO films were grown on glass (GZO), indium tin oxide (IZO), and silicon (SZO) substrates to examine the influence of interfacial growth on structural, electrical, and sensing properties. XRD confirmed highly oriented wurtzite ZnO films with dominant (002) texture, while AFM and SEM revealed significant substrate-dependent variations in surface roughness, morphology, and grain-boundary density. Hall-effect measurements demonstrated notable differences in carrier concentration and mobility, indicating substrate-controlled charge transport. XPS O 1s analysis revealed substrate-dependent variations in defect-related and adsorbed oxygen species, with GZO exhibiting a pronounced defect-related oxygen contribution that contributes to enhanced surface charge transfer and depletion-layer modulation. Gas-sensing measurements toward 1–500 ppm NO showed that GZO exhibited the highest sensitivity, superior selectivity, and stable performance at 107 °C. This enhancement is attributed to substrate-induced microstructure, oxygen-vacancy-mediated surface states, and grain-boundary-controlled charge depletion, highlighting substrate engineering as an effective strategy for improving ZnO-based NO sensors without additional doping or catalytic functionalization.