What is your sample? film, bulk?

Try to use EBSD/EDS.

Also you can use XPS

powder sample, Is there any possibility to identify in PXRD or in EDX spectrum. advice me for Cluster identification other than XPS

Did you tried, UV-vis.. Here you will get the sample spectra, even if you won't observe in PXRD..

Please look out the literature for UV-vis of pure ZnO and compare it..

Is there any possibility to identify the trace amount of ZnO in UV-visible.(RSS or DRS)

Please have a look..

http://onlinelibrary.wiley.com/doi/10.1002/jrs.2511/full

http://pubs.acs.org/doi/full/10.1021/jp048746x

http://pubs.acs.org/doi/full/10.1021/jp300939q