H2 sensing properties of modified silicon nanowires

It has been found that the silicon nanowires modified with noble metals can be used to fabricate an effective H2 gas sensor in the present study.The preparation and surface modification of silicon nanowires(Si NWs) were carried out by chemical methods. The morphology of the silicon nanowires unmodified and modified with nanoparticles of platinum, palladium, silver and gold was investigated using scanning electron microscopy(SEM). The chemical composition of the silicon nanowire layers was studied by secondary ion mass spectroscopy(SIMS) and energy dispersive X-ray analysis(EDX). The structures of type metal/Si NWs/p-Si/Al were fabricated. The electrical characterization(I–V) was performed in primary vacuum and H2 at different concentrations. It was found that the metal type used to modify the Si NWs strongly influenced the I–V characteristics. The response of these structures toward H2 gas was studied as a function of the metal type. Finally, the sensing characteristics and performance of the sensors were investigated.     

Photore sponse and H2 gas sensing properti es of highly oriented Al and Al/Sb doped ZnO thin films

ZnO:Al and ZnO:Al/Sb thin films have been prepared and investigated.The thin films were deposited on Si substrates by the sol-gel method.The structural,optical and electrical properties of ZnO films have been investigated by spectrophotometry,ellipsometry,X-ray diffraction and current-voltage characterizations.It is found that the films exhibit wurtzite structure with a highly c-axis orientation perpendicular to the surface of the substrate,a high reflectivity in the infrared region and a response to illumination.Furthermore,it has been found that Si/（ZnO:Al/Sb）/Al photodiode is promising in photoconduction device while Si/（ZnO:Al）/Al can be used as gas sensor responding to the low H₂concentrations.