I have randomly tested the conductive pastes from Ferro and DuPont. I found out that the Pb-containing conductive paste showed better ohmic contact than Ag paste. For safety reason, I preferred to use Ag one but I have no idea how can I make Ag-conductive paste suitable for glass and Si wafer. One more limitation is that I can't measure Hall voltage at magnetic field exceed 4250 G.
Dear Dr. Chothirawat
Instead of using conductive pastes for electrical contact I will suggest you to deposit metallic film over your sample by vacuum evaporation. Ag may be avoided as it has a tendency to diffuse. You can use Indium if you are not going at high temperatures. For high temperatures, nichrome evaporated films can be used. You can also try gold. Of course, you have to check whether your contact is ohmic or not? A suitable electrical contact is necessary for Hall effect, conductivity or any other electrical measurements. Silver paste is not a good choice.
Dear Dr Kumar,
Thank you for your answer. Many literature suggested that Al or In are the best choice for making electrode. Unluckily, I can't find the supplier both materials (seems stupid reason but it's true). However, I will try using gold bu sputtering again to check the ohmic.
Sincerely yours,
Chothirawat,S
Dear Dr. Chothirawat
I agree with Dr A.Kumar 's suggestions. Further more, I would recommend you to do a RTA(rapid thermal annealing) process after Au deposition, as alloying is necessary for a good ohmic contact.
Hi,
from my experience, thermaly evaporated Al films are suitable to form Ohmic contacts together with ZnO. With the evaporation method, you furthermore have the advantage that your electrode can easily patterned by using appropriate shadow masks.
Dear All,
Thank you for your suggestion. I am looking for Al-conductive paste or other forms. Once I test this material, I will let you know the result to discuss in more detail.
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