Preparation and Characterization of In2O3-CuO Nanocomposite Thin Films as NH3 Gas Sensor

Abstract

An NH3 gas sensor was prepared from nanocomposite films of indium oxide-copper oxide mixtures with ratios of 0 , 10 , and 20 Vol % of copper oxide. The films were deposited on a glass substrate using chemical spray pyrolysis method (CSP) at 400oC. The structural properties were studied by using X-ray diffraction (XRD) and atomic force microscopy ( AFM). The structural results showed that the prepared thin films are polycrystalline, with nano grain size. By mixing copper oxide with indium oxide, the grain size of the prepared thin films was decreased and the surface roughness was increased. The UV-Visible spectrometer analysis showed that the prepared thin films have high transmittance. This transmittance was decreased by mixing copper oxide with indium oxide. The direct optical energy gap ranged 3.5 - 3 eV, which was decreased with increasing copper oxide concentration. The sensitivity of the prepared gas sensor was measured towards NH3 gas at a concentration of 71ppm with operating temperatures of 100, 150, 200, 250 and 30) oC, according to the change of sensor resistance. This sensitivity of the mixture oxides showed a value of about nine times greater than that of individual indium oxide thin films. The results of the optimum gas sensor properties demonstrated a sensitivity value of 75.06%, response time of 10s, and recovery time of 11 s, at a mixing ratio of 20% of copper oxide and an operating temperature of 200oC.

Высокая Чувствительность Пленок Оксида Индия, Полученных Методом Хлоридной Газофазной Эпитаксии, К Аммиаку

“…где ε 0 -электрическая постоянная; ε r -статическая диэлектрическая проницаемость, которая равна 10. [11,41,42]. Несмотря на не столь высокую чувствительность, значения S оказались относительно высокими при существенно меньших n g и T max , что вероятно связано с особенностями структур, которые приводят к высокой чувствительности, но существенно ограничивают быстродействие [35,45,46…”

High sensitivity of halide vapor phase epitaxy grown indium oxide films to ammonia

“…Films In 2 O 3 , obtained by the HVPE method show a very high sensitivity to NH 3 . The values of T max and the corresponding values of the maximum response (S max ) at fixed n g are presented and compared with other papers [11,[38][39][40][41][42][43][44] in Table 3. The most interesting results were shown by NH 3 sensors based on In 2 O 3 [11,41,42].…”

“…The values of T max and the corresponding values of the maximum response (S max ) at fixed n g are presented and compared with other papers [11,[38][39][40][41][42][43][44] in Table 3. The most interesting results were shown by NH 3 sensors based on In 2 O 3 [11,41,42]. Despite the not so high sensitivity, the S values turned out to be relatively high at significantly lower n g and T max , which is probably due to structural features that lead to high sensitivity, but significantly limit the performance [35,45,46].…”