CdO and CdO-ZnO composite nanowires: Synthesis, characterization and ethanol gas response

Abstract

A pure and ZnO added CdO thin films are prepared by chemical bath deposition to study their ethanol sensing properties. The depositions were carried out in a highly alkaline condition where in cadmium acetate was used as a source of cadmium while zinc acetate was added as the source of Zn inclusion. These films were subsequently annealed at 723K and studied for its morphological, optical and gas sensing response to understand the effect of ZnO addition. The optical response for the composite film interestingly depicted the existence of separate absorption signature for CdO and ZnO in visible region at around 550 nm and 360nm respectively, thereby confirming the formation of composite structure. The smooth surfaced CdO nano-wires apparently got transformed in to beaded nano wires with the addition of ZnO. The overall diameter of the CdO wires decreased from around 60 nm to approximately 40 nm for CdO-ZnO composite films. This has remarkably enhanced the ethanol gas sensing response from 39% to 61% for the CdO-ZnO composite thin film.