Modification of the ZnO(0001) Surface by Adsorption of Hydrogen Atoms

The electronic and chemical properties of ZnO surfaces are greatly affected by the adsorption of H atoms. The interaction of H atoms with ZnO(0001) and ZnO(000-1) surfaces has been investigated by temperature programmed desorption (TPD) methods. When the ZnO(000-1) surface is exposed to atomic H at 200 K, one desorption peak of H-2 is observed at 455 K (alpha-peak). In the case of ZnO(0001), two desorption peaks of H-2 are observed at 255 K (gamma-peak) and 455 K (alpha-peak). As H exposure increases, the intensity of the gamma-peak increases as the a-peak is attenuated. The alpha-peak is assigned as the hydrogen adsorbed on O-sites and the y-peak is attributed to hydrogen adsorbed on Zn clusters on ZnO. Zn clusters are produced only on the ZnO(0001) surface as surface O-H bonds are formed.

Automated summary

The study showed that the interaction between hydrogen atoms and ZnO surfaces varies depending on the orientation of the surface, involving adsorption of hydrogen on oxygen sites and Zn clusters. Additionally, an increase in hydrogen exposure led to an increase in the peak intensity of hydrogen adsorbed on oxygen sites, while the peak intensity of hydrogen adsorbed on Zn clusters decreased.