I operate JEOL JSM 7001F. I always found it hard to get good quality images while studying glass substrate (and other non-conductable substrates) samples due to charge accumulation.
Now there's a task for me to get image of 50-70 nm particles on a glass substrate, which seems impossible if i dont use disposition of metal on a surface. Could you please share tips and tricks how you deal with such substrates?
Hello Bulat,
this is an old problem. I have the following idea. You investigate the transmission spectrum of a typical glass substrate. There must be a threshold wavelength where the glass begins to absorb. I assume in the blue or ultraviolett range. Then you irradiate the glass with such a wavelength. The light ionizes the glass and you have contact to ground. If you need a light source: Use a glow cathode. Destroy an old bulb. Then you have a bright spectrum and all wavelengths you need are present. Of course this method may ionize your particle too but if you only need a picture or X-ray analyzis it is no problem.
I hope it works. The Russians are known for unkonventional ideas.
R. Mitdank
Using a conducting layer on the substrate may also be a right way. However, you need to know exact thickness of the layer to estimate the size of the underlying nano particles.
Hello Bulat,
May be you can observe your particles on another substrate, may be silicon or any metal. Another option would be to coat your sample (particles and glass substrate) with a thin conductive coat, usally gold, carbon,... this could distort a bit your particle´s size and shape, but if the coating is thin enough the effects will be negligible. In my experience many common coatings form quite "big" crystals, but a slow deposition can solve the problem. Also Iridium coat is very effective, since the grain size is very very small and the surfaces coated are smooth and therefore distortions of size and shape are minimum.
When you cannot use metal coating there are options to remove the static charge, some use water vapour, but in my experience the best one is to use a localized flow of nitrogen in the close proximity of the sample. It is not perfect, but it means a huge difference when you have to deal with polymers, glass or any other dielectric.
I hope it helps.
Muhammad Shahbaz Anwar , thank you very much, but i just wanted to try to find another way of solving the problem. Coating the sample in a conductor will help, it's certain. The problem being is that the sample must stay as clean as it is possible, excluding contamination of that scale. Thank you for your support.
- Badges
- Science method