Computer image HRTEM simulation of catalytic nanoclusters on semiconductor gas sensor materials supports

In the present work, we have analyzed the feasibility of several metal/semiconductor systems for metal additive superficial clustering. To this aim, we have selected the most common semiconductors (SnO2 and TiO2) and catalytic metal species (Pt, Pd and Nb) used for gas sensing. The application of nanoscopical techniques such as high resolution electron microscopy and the complementary use of the digital image processing (DIP) and computer image simulation (CIS) have shown the morphological characteristics of the metal additive nanoclusters attached to the semiconductor surface. While the natural distribution for Pt on semiconductor nanopowders (SnO2, TiO2…) is as metal nanoclusters, Pd atoms tend to disperse on semiconductor surface and Nb tends to diffuse into the semiconductor bulk. In this work, we show that metal nanoclustering is also possible in the latter cases under special growing conditions such as high metal additive doping or submitting the sample to thermal or reducing processes.