[labnetwork] Cleaning the Surface of ZnO

[Mohamed Ghoneim]

Dear All,

I am sputtering ZnO thin films for pH sensing. Getting repeatable and
stable results is a challenge that I though first has to do with chemical
fouling and other selectivity issues but based on the literature these
issues are there for ZnO but usually do not affect the reliability of
measurements to a great extent. I am more concerned now about the
crystallinity and stoichiometry effects and as well as surface cleaning
techniques to make sure I do not have contaminants on the surface that
significantly affects the surface chemistry.
These are the XRD results of the films (x-axis is 2Theta and the blue (XYZ)
are for ZnO:
[image: Inline image 1]
These are the XPS results of the films (the blue one is the as-deposited
ZnO and the red one is after some tests in buffer solutions):
[image: Inline image 2]

Can you please share thoughts about the effect of (a) Crystalline Structure
and (b) Stoichiometry (or elemental composition) of ZnO thin film on its pH
sensing capabilities and how it affects the surface integrity in terms of: 1-
Sensitivity 2- Repeatability 3- Stability of the Measurments.
All thoughts, comments are highly appreciated,
Thanks in advance and wish you a great day!


Mohamed T. Ghoneim
<https://scholar.google.com/citations?hl=en&user=-5mNcfYAAAAJ&view_op=list_works&sortby=pubdate>
,
Postdoctoral Researcher
MIT Media Lab, Building E-15, Fourth Floor, Room 443g.
Website
<https://sites.google.com/view/mtghoneim>
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