Electroless deposition of aligned ZnO taper-tubes in a strong acidic medium

In this communication, we report the hexagonal ZnO taper-tubes prepared through an electroless deposition method in an acidic medium based on a modified galvanic replacement reaction. Inspection of SEM images of ZnO suggests a one-step, acetic acid in situ crystallization/etching mechanism for producing tubular ZnO arrays. During electroless deposition reaction, the formation process may be rationalized by considering that the etching of ZnO with acetic acid starts from six sites located at the six corners of the top surface of ZnO truncated taper, resulting in a gradual widening of the open holes and tubular ZnO. The present electroless deposition strategy is versatile and with a potential to be developed into a more practical method.