Fabrication of platinum decorated zinc oxide nanorod array-based ultraviolet sensors and their responsivity performance

Metal acts as a passive layer on semiconducter in order to stabilize the surface against chemical and heat-induced changes. The passive layer controls surface recombination, leakage, and related noise as well. In this experiment, platinum (Pt) was coated on the surface of Al-doped ZnO nanorods thin films with two different thicknesses; 5 nm and 15 nm. The trend in current-voltage measurement shows that the resistivity of thin films decreases while the conductivity increases. Meanwhile the 5 nm coating sample shows slightly higher absorbance characteristic but lower photocurrent. The responsivity of 5 nm Pt-coated sample is 94.13 A/W while the sensitivity is 1.23. The 15 nm Pt-coated sample achieved higher responsivity of 153.72 A/W and the sensitivity ratio is 1.24. From this experiment, Pt-coated ZnO shows a good stability for sensing film.