On the correlation between morphology and gas sensing properties of RGTO SnO2 thin films

Szuber, J.; Uljanow, Jerzy; Karczewska-Buczek, T.; Jakubik, W.; Waczyński, K.; Kwoka, Monika; Kończak, S.

doi:10.1016/j.tsf.2005.04.011

Cited by 20 publications

(12 citation statements)

References 15 publications

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“…to NO 2 ) can be increased by optimizing the deposition temperature and thus the substrate surface coverage of Sn droplets. [122] Integration of RGTO-films in micromachined sensor substrates and deposition of Au nanoparticles over the SnO 2 film (Figure 12) has led to successful detection of C 6 H 6 and NO 2 in the ppb range. [14] …”

Section: Spray Pyrolysismentioning

confidence: 99%

Semiconductor Gas Sensors: Dry Synthesis and Application

2010

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Since the development of the first chemoresistive metal oxide based gas sensors, transducers with innovative properties have been prepared by a variety of wet- and dry-deposition methods. Among these, direct assembly of nanostructured films from the gas phase promises simple fabrication and control and with the appropriate synthesis and deposition methods nm to μm thick films, can be prepared. Dense structures are achieved by tuning chemical or vapor deposition methods whereas particulate films are obtained by deposition of airborne, mono- or polydisperse, aggregated or agglomerated nanoparticles. Innovative materials in non-equilibrium or sub-stoichiometric states are captured by rapid cooling during their synthesis. This Review presents some of the most common chemical and vapor-deposition methods for the synthesis of semiconductor metal oxide based detectors for chemical gas sensors. In addition, the synthesis of highly porous films by novel aerosol methods is discussed. A direct comparison of structural and chemical properties with sensing performance is given.

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Section: Spray Pyrolysismentioning

confidence: 99%

Semiconductor Gas Sensors: Dry Synthesis and Application

2010

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“…Die Sensorreaktion (z. B. auf NO 2 ) lässt sich durch die Optimierung der Abscheidungstemperatur, d. h. der Bedeckung der Substratoberfläche mit Sn‐Tröpfchen, noch weiter steigern 122. Der Einbau von RGTO‐Filmen in das Substrat eines Mikrosensors und die Abscheidung von Au‐Nanopartikeln auf einem SnO 2 ‐Film (Abbildung 12) ermöglichte die Detektion von C 6 H 6 und NO 2 im ppb‐Bereich 14…”

Section: Herstellung Von Sensorfilmenunclassified

Homogeneous Nucleophilic Radiofluorination and Fluorination with Phosphazene Hydrofluorides

Mathiessen

Jensen

Zhuravlev

2011

Chemistry A European J

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A series of phosphazenium hydrofluorides, P(1)(tBu)·[(18/19)F]HF, P(1)(tOct)·[(18/19)F]HF, P(2)(Et)·[(18/19)F]HF, and P(4)(tBu)·[(18/19)F]HF, was synthesized. The radioactive phosphazenium [(18)F]hydrofluorides were obtained by the one-step formation and trapping of gaseous [(18)F]HF with the respective phosphazene bases. The [(19)F] isotopomers were prepared from the corresponding phosphazene bases and Et(3)N·3HF. Under the design of experiment (DoE)-optimized conditions, P(2)(Et)·HF and P(4)(tBu)·HF fluorinated alkyl chlorides, bromides, and pseudohalides in 76-98% yield, but gave lower yields with iodides and electron-deficient arenes. DoE models showed that fluorination can be performed in glass vessels, and that the reactivity of P(2)(Et)·HF and P(4)(tBu)·HF is dominated by solvent polarity but is insensitive to water to at least 2 equiv. In contrast, P(1)(tBu)·HF and P(1)(tOct)·HF were unstable towards autofluorolysis. DFT calculations were performed to rationalize this finding in terms of diminished steric bulk, higher Parr's electrophilicity, and chemical hardness of P(1)(R)H(+). The corresponding radiofluorination reaction gave no valid DoE model but displayed similar substrate scope. High specific activity and excellent radiochemical yields with various pseudohalides (81-91%) suggest that the proposed radiofluorination methodology can complement the current [(18)F]KF/Kryptofix methods, particularly in the areas for which nonpolar reaction conditions are required.

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“…Various shapes of nanostructured SnO 2 , including nano-particle-based films [12][13][14][15][16], nano-wires [17][18][19], nano-belts [20,21], nano-rods [22], and selfassembled or pattern-transferred nano-porous structures [23,24], were fabricated and studied for their gas-sensing properties. Currently there are several fabrication approaches for preparation of nano-structured SnO 2 for gas detections, such as sol-gel [12,13,15,[25][26][27], pyrolysis [28][29][30], sputtering [14,31], chemical vapor deposition [32], rheotaxial growth and thermal oxidation (RGTO) [33][34][35][36][37][38][39][40][41][42], etc. Among these processes, RGTO, in which SnO 2 is formed by oxidizing metallic tin films deposited on certain substrates in dry environments, has an advantage in obtaining high aspect-ratio nano-structures [33,42] and controlling the particle size distribution [35].…”

Section: Introductionmentioning

confidence: 99%

“…However, most of the reported SnO 2 devices prepared through RGTO were focused on NO x or CO detections [33,34,[36][37][38]40,41]. Although there were some studies concerning about H 2 -sensing by RGTO-fabricated SnO 2 thin films, either the response magnitude was too low [42] as comparing to the micron-thick un-doped SnO 2 films consisting of nano-particles prepared by sol-gel or pyrolysis [25,28], or the operation temperature is too high (e.g., 450-530 • C [33]), or detailed sensing properties were absent [33,35].…”

Section: Introductionmentioning

confidence: 99%