How to chemically synthesize silver nanoparticles, then grow them into triangular nanoprisms with light from a variety of LEDs. Each color LED creates a different size nanoprism, which has its own characteristic color.
Thermal stress cracking can be completely avoided by CO2 laser cutting thin alumina sheets underwater. I also show how to formulate and apply silver paste, then sinter in a kiln to produce double-sided ceramic printed circuit boards with conductive vias.
60W CW CO2 laser at 80% power. 10mm/sec. Standard lens focal length (50mm). 2mm water above ceramic. 180 passes to cut through 0.75mm thick alumina.
Silver paste: 97% silver powder, 3% glass powder by mass. Particle size 1 micron or less. Add poly vinyl alcohol mold release until desired consistency reached.
Paste applied with 4 mil thick vinyl stencil. Dried in air 10 minutes, then rapidly brought up to 900*C, held for 10 minutes, then rapidly brought back down to room temperature. Total cycle about 45 minutes.
I measured electrical conductivity of the finished traces from my process with vinyl stencils: 4 milliohms per square at 10 micron final thickness. This is pretty close to the Dupont published spec ( less than 2 milliohm/sq at 16 micron thick)
An explanation and demo of atomic layer deposition (ALD) of copper metal on glass. Precursors are copper(I) chloride and hydrogen, processed in a hot-wall tube quartz tube furnace.
10 torr operating pressure
500 sccm argon sweep/purge gas constantly flowing
75 sccm CuCl argon pulse gas (17 seconds including flow controller lag)
100 sccm H pulse gas (14 seconds including flow controller lag)
7 second purge time between pulses
100mm quartz tube furnace diameter
415*C deposition temperature
350*C CuCl evaporation temperature
Substrates are mostly borosilicate glass cleaned with RCA clean
The "good" samples shown in the video are about 750 cycles (about 9 hours