Influence of metal catalyst for zinc oxide nanostructures grown by TCVD method for extended-gate FET sensor application

In this work, zinc oxide (ZnO) nanostructure was synthesized by thermal vapor deposition (TCVD) on various kinds of metal catalyst namely, gold (Au) and platinum (Pt). The thicknesses of the metal catalyst were varied (10 nm and 15 nm) to investigate the shape of the ZnO nanostructures. The metal catalyst was used as seed layer to facilitate the nucleation site for nanostructured growth. FESEM images showed that different shape of ZnO nanostructures were produced on the different type of metal catalyst with different thicknesses. We found that those on Pt catalyst were in the form of nanotetrapod and those on Au catalyst were nanorods. The ZnO nanostructure on Au was tested for its sensitivity in pH measurement for application in extended-gate field effect transistor sensor and a sensitivity of 38.2 mV/pH was achieved.