I fabricate ZnO Nws on bare glass substrates. The experiment was done using quartz tube furnace via thermal evaporation method. The source material is Zn powder. Note that no metal-catalyst, no dopant and no buffer layer involved in this work.The EDX graph also shown other elements like: Si, Na and Mg
Anyone knows the reason for these elements to be appeared in my samples?
Acquire EDS spectrum of your clean substrate (glass). It may have all elements you have mentioned.
I am agree with the comment of V.Dusevich. Besides, you need to have in mind that EDX method is not enough reliable , especially if you do not have adequate standards.
Hi,
It can be a cleaning issue. Use D.I. water for substrate cleaning and then do EDAX of cleaned and uncleaned glass substrate. Water contains these contaminants.
thanks all. yeah, i never thought to do EDX test on the clean substrate. i will do it later. thanks again :)
It is a general topic in analytical chemistry: you have to determine the blank values, you have to estimate the reliability of the measurements and you have to calculate the detection limit. The result of the analysis should be given as a concentration, as a mass fraction or number of atoms molecules... with the corresponding error. The number of digits must be in accordance with your experimental conditions and not with the number of digits given by the calculator. Like 5.32 ng/g ± 0.08 ng/g or better 5.3 ± 0.1 ng/g, with a detection limit 0.07 ng/g. However, my former boss Prof. Tölg stated that the result if only one method is applied is the result of not reliable, first a second independent method have to be consulted to validate the result. Regards Alex
Indeed the signals (you mentioned) are coming from the used glass substrates. To verify that you can scratch out some NWs and put them over a silicon substrate to perform EDS over them.
Please, I have a question:
Does the Energy-dispersive X-ray spectroscopy (EDX or EDS) provide the chemical composition of the material as metal or metal oxide? i.e the results obtained from the EDX are in percent for metal or for metal oxide?
I found in different published papers that the data obtained from EDX are in % of metals and other papers as % metal oxide. When we use it as metals and when as metal oxide?
Is the following sentence right or false: "EDX determines the chemical composition of materials as metals and exposes them as oxides but it doesn't mean that they are oxides". Many thanks for your reply.
Nanowires are small ! Strike a small object with the beam without interaction with what is all around maybe difficult and may be that the reason why you found elements from the glass. May be you'll obtain best result at very low voltage (5KV for example) because the interaction volume will be smaller (you can try to evaluate it with the software CASINO for example). For Zn and O this is possible because the energy of the Zn L alpha is 1keV and the energy of the O K alpha is 0.52keV.
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