Gas-sensitive properties of thin film heterojunction structures based on Fe2O3–In2O3 nanocomposites

Abstract

This paper reports an investigation of the gas-sensitive properties of thin film sensors based on the double-layers Fe 2 O 3 -In 2 O 3 and Fe 2 O 3 -In 2 O 3 /In 2 O 3 towards gases of different chemical nature (C 2 H 5 OH, CH 4 , CO, NH 3 , NO 2 , O 3 ). As it was found, the g-Fe 2 O 3 -In 2 O 3 composite (Fe:In ¼ 9:1, mol) is more sensitive to O 3 ; on the contrary, the a-Fe 2 O 3 -In 2 O 3 (9:1) system, possesses a higher sensitivity to NO 2 . The optimal temperature for detecting of both gases is in the range of 70-100 8C. Sensors based on the g-Fe 2 O 3 -In 2 O 3 heterostructure show the maximum response to C 2 H 5 OH at considerably higher temperatures (250-300 8C), but this layer is practically insensitive to other reducing gases like CH 4 , CO and NH 3 in the same temperature range.An explanation of the different gas-sensitive behavior for the these samples resulted from the particular features of their structure and phase state.

Nanostructured Fe2O3 Thick Film as an Ethanol Sensor

“…Iron oxide, metal oxide semiconducting material, can exist in various forms such as α-Fe 2 O 3 , γ-Fe 2 O 3 and Fe 3 O 4 . The gas sensing properties of α & γ forms are still not established and contrasts are available in Iron oxide literature [1,2]. Some papers attribute to gas-sensing properties of γ-Fe 2 O 3 and Fe 3 O 4 rather than to α-Fe 2 O 3 .…”

“…Some papers attribute to gas-sensing properties of γ-Fe 2 O 3 and Fe 3 O 4 rather than to α-Fe 2 O 3 . The α-Fe 2 O 3 form has been recognized as having minimal gas-sensing response [1] It has been reported that the thermal stability of the γ-Fe 2 O 3 limits its use as gas sensor [2] Iron titanium oxide solid solutions have shown response to ethanol [3]. Some report says α-Fe 2 O 3 , the most stable iron oxide with n-type semiconducting properties under ambient conditions, is extensively used as gas sensor, catalysts [4,[5][6][7][8][9].…”

Fabrication and characterization of Fe1.90Ti0.10O3 gas sensitive resistors for carbon monoxide

“…There are a few scattered reports which discuss the potential of iron oxide as a gassensing material [8][9][10][11][12][13][14][15][16][17]. Iron oxide can exist in various forms such as ␣-Fe 2 O 3 , ␥-Fe 2 O 3 and Fe 3 O 4.…”

“…Iron oxide can exist in various forms such as ␣-Fe 2 O 3 , ␥-Fe 2 O 3 and Fe 3 O 4. The gas-sensing properties of the ␣ and ␥ forms are still not established and contrasts are available in literature [10,15]. Some reports attribute the gas-sensing properties of iron oxides to ␥-Fe 2 O 3 or Fe 3 O 4 forms rather than to ␣-Fe 2 O 3.…”

Influence of electrical characteristics on the sensitivity of p-InP-based pseudo-Schottky diodes for NO2 monitoring in atmosphere

“…However, they suffer from many problems: high working temperatures and high threshold values compared to atmospheric pollution concentrations. Many metal oxides gas sensors can be also used; such as tin oxide (SnO 2 ) [8,9], indium oxide (In 2 O 3 ) [10][11][12][13] or tungsten oxide (WO 3 ) [14][15][16][17]. In general, they show high sensitivity and reproducible results, but they need work at elevated temperatures.…”