Hydrogen sensitivity of the sensors based on nanostructured lead sulfide thin films deposited on a-SiC:H and p-Si(100) substrates

• Nanostructured PbS thin films were obtained from different aqueous solutions.
• The as deposited thin films were used as sensing elements in H2 gas sensor.
• The morphological and electrical properties were investigated.
• H2 gas sensing tests of these sensing elements were also done.
• A high sensitivity to H2 gas with films grown in bath containing PVA.

In the present study, we have carried out the adsorption effect of H2 on lead sulfide nanocrystalline thin films based gas sensors by measuring the variation of their current–voltage characteristics (I–V). The PbS thin films were synthesized by modified polyol process on amorphous a-SiC and p-Si(100) substrates in different chemical bath deposition. The obtained thin films were examined by Scanning Electron Microscopy (SEM) and Rutherford backscattering spectrometry (RBS) to get the general view of the product formed such as morphology and elemental composition. The films conductivity was n-type. We have obtained high density of uniform PbS nanocrystalline thin films. Upon exposure to gaseous molecules, the current at forward bias of nc-PbS decreased. The mechanism of gas sensing procedure was discussed. These sensors are highly sensitive with fast response to H2 gas. Our results have shown that nc-PbS thin films have potential to be a good H2 gas sensor at room temperature.