Cu-Doped ZnO Thin Films Deposited by a Sol-Gel Process Using Two Copper Precursors: Gas-Sensing Performance in a Propane Atmosphere

Abstract

A study on the propane gas-sensing properties of Cu-doped ZnO thin films is presented in this work. The films were deposited on glass substrates by sol-gel and dip coating methods, using zinc acetate as a zinc precursor, copper acetate and copper chloride as precursors for doping. For higher sensitivity values, two film thickness values are controlled by the six and eight dippings, whereas for doping, three dippings were used, irrespective of the Cu precursor. The film structure was analyzed by X-ray diffractometry, and the analysis of the surface morphology and film composition was made through scanning electron microscopy (SEM) and secondary ion mass spectroscopy (SIMS), respectively. The sensing properties of Cu-doped ZnO thin films were then characterized in a propane atmosphere, C3H8, at different concentration levels and different operation temperatures of 100, 200 and 300 °C. Cu-doped ZnO films doped with copper chloride presented the highest sensitivity of approximately 6 × 104, confirming a strong dependence on the dopant precursor type. The results obtained in this work show that the use of Cu as a dopant in ZnO films processed by sol-gel produces excellent catalysts for sensing C3H8 gas.

Synthesis and characterization of Cu doped chromium oxide (Cr2O3) thin films

“…All peaks are identical to those corresponding to the Cr 2 O 3 phase indexed in the rhombohedral structure with an R-3c space group, as described in the 072-3533 JCPDS card [31,32]. The strong intensity of the peaks representing the preferential orientation in the (104), (110) and (116) planes indicates that thin films exhibit good crystallinity [33]. Additionally, it is evident that no extra phases corresponding to either copper or copper oxides were detected from this technique.…”

High-Performance Flexible Ultraviolet Photodetectors with Ni/Cu-Codoped ZnO Nanorods Grown on PET Substrates

“…In addition, no impurity traces or any other diffraction peak related to secondary phases from Cu, Cu 2 O, CuO, Ni, or NiO was detected within our XRD detection limit. This result suggests that Ni or Cu dopants used in this study did not form any new heterogeneous compound phases in the ZnO crystal but dissolved into the lattice matrix as a dopant [31].…”

Sensitive detection of hydrocarbon gases using electrochemically Pd-modified ZnO chemiresistors

“…This is probably because of the lower film porosity. A high film porosity is necessary to obtain better results with this HCs gas sensing mechanism [49–50]. …”