On an indium–tin-oxide thin film based ammonia gas sensor

Current-voltage characteristics in macroporous silicon/SiOx/SnO2:F heterojunctions

“…Fluorine-doped tin oxide SnO 2 :F(FTO) and porous silicon (PS) are two types of materials that have been extensively investigated for sensor applications [1,2]. Tin oxide is a transparent conductive oxide with electrical transport properties extremely sensitive to the environment [3-6].…”

Highly selective ppb-level detection of NH3 and NO2 gas using patterned porous channels of ITO nanoparticles

“…Therefore, we carried out our gas experiments in dry air in order to eliminate humidity effect. It is known that the sensing mechanism of ITO-based sensors towards NH 3 gas depends on the interaction between the reducing gas and the adsorbed oxygen ions on the ITO surface, thereby causing an increase of conductance according the following reaction [16,29]: 2NH 3,gas + 3O − (ads) → N 2 + 3H 2 O + 3e − . On the contrary, NO 2 gases are adsorbed as negatively charged molecules on the ITO surface resulting in a decrease of conductance, as described by following equation [12,14]: NO 2,gas + e − → NO 2 − ,ads .…”

“…In fabricating these sensors, metal oxide-based semiconducting materials such as SnO 2 , NiO, ZnO, Ga 2 O 3 , TiO 2 , In 2 O 3 , and tin-doped indium oxide (ITO) have been regarded as promising sensing materials for gas detection due to their high sensitivity and compatibility with conventional microelectronic fabrication process [6][7][8][9][10][11]. Among them, ITO-based gas sensors have shown high electrical conductivity and optical transparency while being used for the detection of diverse gases such as CH 3 OH, H 2 , NO 2 , CO, NH 3 , and HCHO due to its good sensitivity, low operating temperature, and good compatibility with standard IC fabrication [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Moreover, it can be utilized in smart window and wearable nose-sensor applications, where both high optical transparency and gas sensitivity are demanded [26,27].…”

“…Moreover, it can be utilized in smart window and wearable nose-sensor applications, where both high optical transparency and gas sensitivity are demanded [26,27]. So far, most of the ITO-based gas sensors were based on thin film structures, mainly due to the relative easiness and low cost in their fabrication process, however, these ITO thin film-based sensors showed some drawbacks such as low sensitivity and poor selectivity for specific gases [12,16,28]. In particular, there have been several efforts to increase the sensitivity by increasing the surface-to-volume (S/V) ratio of the ITO thin films by utilizing rough films, nano-grained films, or ITO nanoparticles (NPs) [14,23,[29][30][31].…”

Ammonia quantitative analysis model based on miniaturized Al ionization gas sensor and non-linear bistable dynamic model

“…[1][2][3] Many researchers develop novel materials to fabricate ammonia gas sensors. [4][5][6][7][8][9][10][11][12][13] Since the discovery of the catalytic effect of SnO2 in 1962, many studies have been conducted to improve sensor's functions. 14,15 Since proposed by Benzi in 1981 for the earth ice age disciplinarian explanation, 16 bistable dynamic model has been widely applied in fields, such as signal detection, electrical circuits, biological modeling, neural systems, et al [17][18][19][20] It is interesting that, under certain circumstances, an extra dose of noise can actually help the performance of some devices, by eliminating the internal noise in the system.…”