[labnetwork] Should a pH Sensing Membrane be Conductive or Insulating?

[Mohamed Ghoneim]

Thanks Bill for the helpful tips and the note. Apologies for the research
specific query.

Wish you all 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>

On Wed, Jan 31, 2018 at 4:05 PM, A. William (Bill) FLOUNDERS <
bill_flounders at berkeley.edu> wrote:

> Mohamed Ghoneim,
> Your gate insulator should be highly insulating.
> You are attempting to monitor the degree of protonation of
> surface hydroxyl groups as a function of solution pH.
>
> I encourage you to review detailed principles of operation
> and review articles from research group of Piet Bergveld. (1980 -2000).
> I will continue conversation with you offline.
>
> I repeat my regular proposal / request that labnet not host such detailed
> research specific inquiries. I welcome ongoing discussion of our network.
>
> Bill Flounders
> UC Berkeley
>
> On Wed, Jan 31, 2018 at 6:28 AM, Mohamed Ghoneim <
> mohamed.t.ghoneim at gmail.com> wrote:
>
>> When using EGFET pH sensing configuration (very similar to a
>> metal/sensing membrane to collect ions from solution and generate
>> voltage).....does the sensing thin film have to be conductive or insulating?
>>
>> Example Setup:
>>
>> [image: Inline image 1]
>>
>> I am using EGFET setup with commercial transistor that is connected to a
>> Au electrode with a ZnO thin film (150 nm) on the part to be immersed in
>> solution to sense the pH. I also use a reference electrode to set the
>> offset voltage and bias the transistor.....does my ZnO thin film have to be
>> conductive or insulating for reliable sensor performance?
>>
>> It is generally reported in literature that the preferred orientation of
>> ZnO used for such purposes is (002) although few reported amorphous....but
>> conductivity is not usually discussed. Since ZnO's conductivity is highly
>> tunable, it would be very helpful if its conductivity matches the
>> requirement for a good sensitivity and reliable measurements.
>>
>>
>> All responses and discussions are appreciated...thanks in advance,
>>
>> 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>
>>
>> _______________________________________________
>> labnetwork mailing list
>> labnetwork at mtl.mit.edu
>> https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork
>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mtl.mit.edu/pipermail/labnetwork/attachments/20180131/e920332e/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 59636 bytes
Desc: not available
URL: <https://mtl.mit.edu/pipermail/labnetwork/attachments/20180131/e920332e/attachment.png>