Nanosized thin SnO₂ layers doped with Te and TeO₂ as room temperature humidity sensors.
In this paper the humidity sensing properties of layers prepared by a new method for obtaining doped tin oxide are studied. Different techniques-SEM, EDS in SEM, TEM, SAED, AES and electrical measurements-are used for detailed characterization of the thin layers. The as-deposited layers are amorphous with great specific area and low density. They are built up of a fine grained matrix, consisting of Sn- and Te-oxides, and a nanosized dispersed phase of Te, Sn and/or SnTe. The chemical composition of both the matrix and the nanosized particles depends on the ratio R(Sn/Te) and the evaporation conditions. It is shown that as-deposited layers with R(Sn/Te) ranging from 0.4 to 0.9 exhibit excellent characteristics as humidity sensors operating at room temperature-very high sensitivity, good selectivity, fast response and short recovery period. Ageing tests have shown that the layers possess good long-term stability. Results obtained regarding the type of the water adsorption on the layers' surface help better understand the relation between preparation conditions, structure, composition and humidity sensing properties.
Institute of Optical Materials and Technologies "Acad. J. Malinowski", Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl.109, Sofia 1113, Bulgaria. biliana@iomt.bas.bg.
Biliana
B
Georgieva
Institute of Optical Materials and Technologies "Acad. J. Malinowski", Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl.109, Sofia 1113, Bulgaria. irena18@gmail.com.
Irena
I
Podolesheva
Institute of Optical Materials and Technologies "Acad. J. Malinowski", Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl.109, Sofia 1113, Bulgaria. gspassov@iomt.bas.bg.
Georgy
G
Spasov
Institute of Optical Materials and Technologies "Acad. J. Malinowski", Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl.109, Sofia 1113, Bulgaria. jordan_pirov@abv.bg.
Jordan
J
Pirov
D006813:Humidity; D008855:Microscopy, Electron, Scanning; D015336:Molecular Probe Techniques / Q000295:instrumentation; D049329:Nanostructures; D012680:Sensitivity and Specificity; D013691:Tellurium; D013696:Temperature; D017971:Tin Compounds
D017971:Tin Compounds; C016774:tellurium dioxide; C045358:stannic oxide; D013691:Tellurium