Last week, I reported on the the morphology of pnc-Si deposited with different substrate biases. We hypothesized that the reason for this was due to the different initial film stress of the as-deposited a-Si. Unfortunately, the pressure-displacement method does not allow us to measure amorphous films since it requires the membrane to be nearly flat…

Hi everyone! I’m sifting through the mass of data I collected during my last month and am compiling posts to update everyone. This post shows the latest with the microfluidic chamber that Henry and I designed.  In my first post regarding this device, I showed microparticle and blood flow over cultured endothelial cells (bEnd3).  In…

It seems that pores are only formed in the “sandwich structure” on certain process. So in order to verify this conclusion, I annealed two layers structure (20nm sio2+15nm si) to test the agglomeration theory. The other parameters in depositing and annealing are same to typical sandwich structure process (1000°C anneal, ramp rate 100c/s, w/o bias,…

UPDATE: A look at long and short crystal dimensions (9/1/10): DLS vs. Crystal Sizes – Newest version 8/30/10 Here is a comparison of sieving curves using DLS or estimated crystal dimensions of proteins. DLS: 24 hours sieving curve. 48 hours sieving curve. Estimated longest crystal dimension: 24 hours sieving curve. 48 hours sieving curve.

We have always speculated that the substrate bias during the a-Si deposition had a strong effect on pore morphology of pnc-Si. Here, I looked at three 15 nm silicon films deposited with 00W, 25W, and 50W substrate bias. Recall, that the substrate bias applies rf energy to the substrate surface so that impinging Si atoms…

These are cross sections of my comsol diffusion model.  Each chip has 6 square wells terminated in a membrane.  This cross section cuts across the two middle wells.  Concentration contours are in 0.025 intervals. 6 hours: 12 hours: 18 hours: 24 hours:

Over the last couple of weeks, I’ve been doing confocal fluorescence microscopy over at the Med Ctr.  I was hoping this tool would clean up some of the background fluorescence in my immunofluorescent images.  More importantly, the confocal can take ‘slices’ of images in the z-plane and stack them on top of each other to…

As a proof-of-principle, Henry and I have been working on a microfluidic device for flowing blood cells/particles across cultured cells on pnc-Si.  More on why this is important later.  We’ve come up with a prototype and I’ve been testing it out.  I will include schematics later but here are the first couple of movies I’ve…

One of the points I’d like to discuss in my co-culture paper is the advantageous imaging qualities of pnc-Si compared to ‘translucent’ commercial transwell membranes.  This has been evident in many of my posts of Live/Dead stained cells, even at 20X.  I thought a higher resolution (100X) image would emphasize this point even more since…

In order to figure out the relationship between grain size and pore size, I tried to use XRD measurement to determine the grain size by Scherrer equation. t = kλ/(B cosθ) where t is the average grain size, k is the shape factor that is in the range 0.87-1.0 (it is usually assumed to be…