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Chemical precursor-dependent dual effect of doping on the gas-sensing performance of metal oxide semiconducting materials   
Yazarlar
Ahmad Ajjaq
Gazi Üniversitesi, Turkey
Fatih Bulut
Sinop Üniversitesi, Turkey
Prof. Dr. Özgür ÖZTÜRK
Kastamonu Üniversitesi, Türkiye
Selim Acar
Gazi Üniversitesi, Turkey
Özet
In this study, we report a chemical precursor-dependent dual effect of doping on the gas-sensing performance of metal oxide semiconducting materials. Our findings challenge the conventional notion that optimal doping consistently enhances gas-sensing properties. Acetate and nitrate salts were used as chemical precursors, lanthanum (La) was used as a dopant, and ZnO was used as a semiconducting material. All materials were synthesized under identical conditions by a two-step process involving dip coating and hydrothermal methods. Gas-sensing results demonstrated an improvement in the performance of the acetate-based doped film and a decline in that of the nitrate-based doped film compared to their respective pure counterparts. Among the produced sensors, 1 wt% La-doped ZnO sensor produced by the acetate precursor proved to be convenient for usages in real markets. It showed superior performance with a high response (62) at a relatively low operating temperature (150℃) towards 50 ppm of NH3 gas. The sensor also demonstrated exceptional baseline stability, high short-term and long-term consistency, good selectivity, and strong tolerance to humidity (up to 70 RH%) with slightly slow adsorption-desorption rates. The dual effect was discussed with respect to dopant- and precursor-induced variations in structural and surficial characteristics, revealed by XRD, Raman, FESEM, AFM, and XPS. The discussion delved deeper into the role of chemical precursors on nanostructure growth and, for the first time, illuminated a temperature-dependent complex gas-sensing principle governed by the detected p-n shift of the semiconductor type of the sensing elements, confirmed by Hall effect.
Anahtar Kelimeler
Doping | Lanthanum | NH gas sensor 3 | p-n shift | Precursor | ZnO
Makale Türü Özgün Makale
Makale Alt Türü SSCI, AHCI, SCI, SCI-Exp dergilerinde yayımlanan tam makale
Dergi Adı Sensors and Actuators B: Chemical
Dergi ISSN 0925-4005
Dergi Grubu Q1
Makale Dili İngilizce
Basım Tarihi 12-2024
Cilt No 420
Sayı 1
Doi Numarası 10.1016/j.snb.2024.136501