Epitaxial Electrodeposition of ZnO/Dye Hybrid Single Crystal Thin Films

点击翻译按钮获取中文摘要

Heavily doped conductive bulky single crystals of GaN were employed as rotating disk electrodes (RDE) to study their activities towards reduction of oxygen and to attempt epitaxial electrodeposition of ZnO by cathodic electrolysis in oxygen saturated aqueous solution containing ZnCl_2. For GaN(0001) cut, it was found that N-terminated surface was completely inactive for O_2 reduction, while Ga-terminated surface exhibited moderate activity. Several surface treatments were applied. Long-term electrolysis in Zn^<2+>-free KC1 solution was found as most effective to activate the surface. Koutecky-Levich analysis revealed that the standard charge transfer rate constant was improved from 1.1 × 10^<23> to 2.4 × 10^<-14> cm s^<-1> from the untreated one to the one activated by electrolysis, although it is still much smaller than that for FTO coated glass (4.1 × 10^<-7> cm s^<-1>). The activation was effective also to improve the quality of the epitaxial ZnO(0001)growtii as checked by the XRDC-scan.The GaN(1100) cut exhibited the higher activity than (0001) and yielded ZnO(1100) single crystal film with the higher degree of epitaxy. There has been not too many precedent examples of epitaxial ZnO growth for non-polar surface and the present results indicate high possibilities with the electrodeposition method.