NRG

PhD Dec. 15, 2010 Thanks for Everything!

In continuation of work on ultrathin metal electrodes on pnc-Si, I tried changing metal thicknesses at different positions inside the chamber.  In this experiment, on the front side of the 30 nm thick membrane the 22 nm metal layer was deposited from three different positions in the same run. The back sides of all the…

This is an update of the research on the on-chip EO pump. Due to a mistake in determining the direction of particle flow, it now looks like the particles in this post were moving by electrophoresis rather than electroosmosis.  The particles were negatively charged (-40 mV zeta potential) because of a COOH group on the…

Using fresh tips, I re-ran the scans of amorphous Si films deposited at different biases. Recall that our theory states that interface roughness between the Si/SiO2 is an important determinant for ultimate pore morphology. A rough interface will suppress nucleation, which is why we observe low porosity with zero bias. The 05 W condition decreases…

In my last post, I introduced the concept of pore size dependent carbon growth on alumina coated membranes. Here, I have plotted a Gaussian fit of the tail of the pore size distribution of carbonized membranes (with and without an alumina coating). I am only showing the tail of the distribution to highlight the sharpness…

Based on previous data, we have seen a reduction in pore size and porosity when we increase the oxide thickness. For this experiment, we compare asymmetrical oxide thicknesses with symmetrical oxide thicknesses to observe which layer has the dominate effect on pore size and porosity. Wafer 718 is a 40/15/40, 719 is a 20/15/20 and…

To follow up on some of Dave’s work – I was curious if the ALD alumina affects the strength of pnc-Si membranes. Punchline: 2.5 nm of Alumina seems to increase the burst pressure, while 5.0 nm reduces the burst pressure. Methods: As part of routine QC, we had already measured robustness on 6 SepCons to…

This week, I did a systematic study on the growth rate of carbon on bare and aluminum oxide coated pnc-Si membranes. The bare samples were not treated prior to carbonization, while the alumina coated samples underwent a 5 nm treatment in the ALD tool. A bare and alumina coated sample were placed together inside the…

I am trying to deposit metal on the membrane with minimal deposition inside the pores. The image below is an example of how the film quality and thickness change when the sample is positioned at different angles and distances from the source in the same deposition run. The schematic in the corner of each SEM…

For the charge model, we would like to know the surface charge density and size of our experimental molecules.  I’ve attempted to use the Zetasizer for both measurements, but as mentioned in my diffusion paper, DLS gives sizes that deviate from the expected or crystal sizes.  Since zeta potential measurements require large amounts of highly…