Dear Vimal Kumar Singh Yadav , if your FESEM has a local nitrogen gas injector, my advice is to use it very close to the ZnO NWs, in this way the static charge is removed fairly well, allowing to obtain good resolution images. I use this trick together with a low voltage (usually below 5kV). The N2 cannula should be very very close to the sample. This cannula is made of some elastic polymer.

Another good option is coating your sample with Iridium. It is a conductive layer, but unlike gold or carbon allows to coat the sample with very thin and smooth layers, so you only need to add a few nm thick layer (in my case often just 5nm is enough). I use magnetron sputtering to do so.

Hope it helps.

It depends on the substrate of your NWs. If the substrate is conductive(Si...), then you don't need to coat.

FESEM is capable of low voltage operation. You can observe most insulators applying voltages in between 0.7 to 1.3 kV, you need to check (while imaging) which voltage is the best for your specimen. It may occur, as I understand, that your nanowires are conductive, then you may want to go to higher voltages, like 3-5 kV.

Check if your SEM support a low vacuum specimen chamber

https://www.jeol.co.jp/en/words/semterms/search_result.html?keyword=low-vacuum%20SEM#:~:text=The%20Low%20vacuum%20SEM%20(LV,%2DSEM%20(product%20name).

Dear Xin Liu, Vladmir sir and M A Bakr sir..thanks a lot for your worthy response. It is really helpful