Silver Mirror again on TMD

SiO2 substrate has different characteristics than MoS2, and forming silvers on the surface is often easier. They are both amorphous, but it is essential to rerun the silver on the SiO2+MoS2 substrate to be positive. It is much better to fail my silver mirror on the MoS2 sample now than when I go through the lithography process to form a transistor. I will cut my substrate in half to once again run the silver mirror test back according to my own protocols and ratios I previously used.

I tried using a diamond scratcher again to cut the substrate, but it shattered because the substrate has glass-like characteristics. I was not careful enough with the scratcher, and I could only spare one half-sized substrate for the test instead of two so I needed to ensure I performed today’s experiment with maximum accuracy.

PROTOCOL

• Washing the substrate with Acetone and Deionized Water
• Prepare atleast 10ml of 0.1M AgNO3, 0.8 + 0.1(6) = 1.4ml of 12.5–14% diluted Ammonia, and 2ml of 5% glucose
• Adding the fixed amount of Ammonia to Silver Nitrate, and keep adding little by little(0.1ml) until most of the silver particles dissolve to create a clear solution.
• Add the fixed amount of glucose and wait.
• Once the reaction is done, look at it under a microscope to see the results.

STUDY

The Glucose solution is the reductant, and the ammonia solution makes the silver ions less susceptible to the reduction. Therefore the ammonia solution will slow down the reaction the more you add, and if you add the right amount, the reaction will occur slow and steady which is what we exactly want. The reaction should be slow because often when the particles rapidly form in the beginning, it is not evenly distributed throughout, and it will not have a consistent and smooth surface. However, once the reaction slows down, the particles will slowly form and fill the uneven spots to create a smoother surface. This is the theory I took advantage of, and if you slow the reaction down by adding ammonia until the solution becomes clear, it will slow the reaction down, and it can slowly form silver particles to create a consistent surface of the silver.

Pre-Experiment steps

• I created more amounts diluted solution than I was going to use according to my protocol just in case to prepare to adjust it according to how each reacted with each other.
• Glucose dilution 0.2g of Glucose + 4ml of H2O = 0.2/4 = 0.05 = 5%

• 3ml of 25–28% NH3 + 3ml of H2O = (3/(3+3)) x 25–28 = 0.5x25–28 = 12.5–14%

• Labeling all the solutions

EXPERIMENT

• 10ml of 0.1M AgNO3 + 0.8ml of 12.5–14% NH3 and adding 0.1ml total of 6 times until the solution became clear. This creates AgOH + NH4NO3

• Adding 2ml of 5% Glucose solution to the AgOH + NH4NO3 = and dipping the substrate in with the mixture.

• I recommend you watch the video to see the whole process. https://youtu.be/QHKL-59vlvY
• Result

The blue color is the non silver side(MoS2) and the purple is the silver reflecting light. You can find barely any holes through out and as I went towards the side with not as much MoS2 flakes, I saw more holes but it was very minimum overall. I think it was successful even though it was my first try.