Nanoparticle films made by gas phase synthesis: comparison of various techniques and sensor applications

Abstract

Nanoparticles can be generated by several different gas phase methods, such as gas deposition, laser-assisted chemical vapor deposition, and laser ablation. Some of the most important aspects -such as size-distribution, structure, and chemical composition of the generated nanoparticles (specifically W and WO 3 ) -are presented and compared. WO 3 nanoparticle films were deposited by an advanced gas deposition technique and were tested for sensor applications. Two different sensor devices were fabricated: Firstly, a thin Au-WO 3 nanoparticle sandwich film was constructed, and conductance fluctuations of the Au film were measured as the sensor was exposed to alcohol vapor. Secondly, conductivity changes of a thick WO 3 nanoparticle film were detected as it was exposed to test gases (H 2 S, NO 2 , and CO).

Gas-deposited WO 3 nanoparticles studied by scanning force microscopy

“…12 WO 3 -based sensors can be used for detecting hazardous pollutants such as NO, NO 2 , 13 and H 2 S. 14 Thermal stability studies on nanoparticle films of WO 3 did not indicate any increase of the crystallite size for heat treatment at temperatures up to 300 °C. 15 However, it is not clear whether agglomeration of the particles occurs in this temperature range.…”