From your question I deduced you deposite/precipitate your oxides on a substrate to be observed by means of TEM. I am not familiar with this method for specimen preparation, and I don't know which methods did you already try, but I'll try to give you some quick hints about the techniques I used/I know for TEM specimen preparation. The simplest method is to prepare a suspension with your powdered sample and deposite it on the TEM grid (if you don't care about textural features). You can also try to include the film sample in resin and a) polish it like you were preparing a conventional thin section, or b) produce electron-transparent slices by ultramicrotomy, and attach a grid on it. I hope this was useful to you. It depends on how do you deposite your oxides. There are also other techniques but I think these are the most coherent for your study.

Dear Cristina, Thanx for your answer.

I deposit my oxide material (Yttria stabilized zirconia) by pulsed laser deposition technique (Physical vapour deposition technique). Thinning the thin film samples (200-500 nm) mechanically will damage the thin film. So I want to try a technique similar to NaCl crystal technique in which the NaCl crystal can be removed by simply dissolving in water. The NaCl crystals are too costly to me as I am a student.

When you said that you used NaCl as a substrate for deposition, I thought on a method that allowed you to prepare a cross-section of your material but including your substrate, as it is done in material sciences. Taking into account the thickness of your films, I think that in your case the ultramicrotomy would give you good results (perhaps it may not be a student-budget tecnhique). After NaCl dissolution, how do you attach the film to a Cu grid?

Hello, an inexpensive way to obtain NaCl substrate is to cold-press salt powder! I do not know how to manipulate your thin film when it will be in the water but if it contains high internal stress level, it could also be destroyed during dissolution in water.... Regards

Dear Cristina, I usually deposit the desired material on Si substrate. But for TEM observation of planar section (not cross-section), I want free standing film. If I deposit on a NaCl substrate then after dissolving in water the self standing will come out as NaCl dissolves in water and then a Cu grid can be used to take out the film. Note: I read this method from journal articles. I have never used this method.

Thanx Cedric, I was thinking of this technique. I will try it.

You can try depositing the film onto a fugitive substrate such as C or camphor then sinter the film that comes out free standing

Dear Cristian S., crystallinity might change if I sinter.

One of the possible method is to prepare a photoresist thin layer on a clean supporting glass plate (easy by dipping the glass into photoresist or by spinning), drying the photoresist and depositing of your film on it. In a final you simply dissolve the photoresist in acetone. The method works perfectly for free standing metallic films. For oxides I have never tried.

Subhasisa,

Manual polish and thin is very established in the thin film community, and is unlikely to damage your film to a large degree. There is plenty of online info available, though know how and skill are involved.

Workers have recently developed methodologies to "skim" a thin specimen from the top of a sample for plan view TEM, but this technique is just emerging...

Thanx Colm, I have also seen some literature about manual polishing and thought to do.

You can try to deposit the oxide film on thin carbon film supported by a TEM grid. In this case no need for any other sample preparation.