This question is too general. You better define which kind of surface defects. You need different tools to characterize defects according to their physical and chemical properties.
I also believe that you should be much specific on your question, because these can be characterize from spectroscopy to microscopy using different tools.
Thanks Woojoon, Niyazi Al-Areqi and Anming... Could you explain in detail about ICP and XPS?...How to analyse XPS data, how it helps in determining the polar facet? ICP is used to identify the unknown elements present in the sample know?