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W5: Undecided between (semi) conductor in polymer, some in the polymer, some wet, all wet with resins/binders, and all wet with just hot plastic making everything stick in place.

W4: For variability, shelf-life (oxidation) and constant deposit rate are key. Test patterns on silicon for after-the-fact. Resistance testing is useful/common. Laser cutter can oblate/cut sections and rely on a redundant section. Acid etching may be possible. Heating and removal may be possible. "MISFET" metal-insulator semiconductor field effect transistor. Schottky diode--metal (Schottky)-semiconductor-metal (ohmic) sandwich. Work function of metal versus electron affinity in semiconductors essentially the same. Bonds covalent. Electrons move into metal and becomes less [pn]-type. Barrier forms where electrons left and voltage happens. Difference in other direction causes flow of electrons and ohmic contact. Can either vary metal or doping. Lookup leaky / Schottky diodes versus regular pn-junction. Schottky transistors also possible.

In the end we want CMOS to save material. NAND CMOS is 4 transistors. TTL has 3 transistors and 4 resistors. Also, CMOS has much better fanout. Look into verilog/VHDL output.

For Thursday: carbon. Keep thinking about deposition method. Get transparencies from John.

W3: Deposition method. Automatic dropper? Like an aquarium pump but very small. Called automated pipettes. Sticking to the sides depends on the charge, but Meehan hasn't encountered problems--gold and cadmium sulfide don't.

W2: Carbon as the Conductor material (and potentially resistors, capacitors and inductors) Step 1: Put a wire on a substrate (paste or liquid preferable to powder)

W1: document material and process choice, investigate printing, inert substrate

Materials and Processes

Material Doping Process Notice
Silicon Mix in during boule creation and ion implantation (particle acceleration with phosphorus or arsenic and boron or gallium) or furnace with gas (diffusion) Need at least 10 kEv. Heat treatment for recrystallization (electrical activation) afterwards. Silicon dioxide mask for gas
Organic semiconductors Beaker chemistry, dissolve into solvent
Graphene Doping during furnace and gas formation
Zinc sulfide
2-6 semiconductors Beaker chemistry, small particle slurry


  • Carbon, gold don't oxidize
  • Aluminum, silver, copper


  • Electroplating to recover metals (different voltages for different metals)/
  • Size-selective precipitation technique if p, n had different sizes
  • Selective etches
  • Focused ion beams to bombard off surface