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I've looked around at quite a few websites to see if it is possible to make a transistor at home. I found that recently they have successfully "printed" nanocellulose using an ink jet printer (https://hackaday.com/2021/05/12/3d-printed-transistor-goes-green/). However, I doubt that ink would be something you could easily acquire at home.

I wondered why powdered doped silicon printed out of an inkjet wasn't done but I'm guessing it is too porous or something to make it effective. Also the "secret yellow dots" (https://en.wikipedia.org/wiki/Machine_Identification_Code) would probably really mess up your circuit. I looked into fox hole radios (there's a PN junction there) and that is not reliable because you have to find a "hot spot".

While searching stack exchange someone mentioned that DIYers had previously made "point-contact transistors". It appears that it is two pieces of gold foil with germanium in between. As exciting as printing out gold dust slurry and germanium slurry would be on an ink jet... ... would it be possible to use gold foil and germanium foil and a dot matrix printer to "stamp" a transistor out by layering them? I'm sure the best solution is "just try it", but hopefully there is someone that knows the physics well enough to know if it is possible.

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    Have a look at the very first transistor made. || Wikipedia: John Bardeen, Walter Brattain and William Shockley invented the first working transistors at Bell Labs, the point-contact transistor in 1947. – Russell McMahon Jul 25 '21 at 02:24
  • Bardeen and Brattain used germanium, rather than galena, in their first point contact transistor. Of course, if you want "reliable" then that's probably out. In fact, that's why Shockley developed the bipolar -- to make it sufficiently reliable. (Well, that's funny. Saying almost the same thing. ;) I guess it must be true, then.) – jonk Jul 25 '21 at 02:25
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    google `jeri ellsworth diy transistor` – jsotola Jul 25 '21 at 03:06
  • What Jsotola said [here](https://www.google.com/search?q=jeri+ellsworth+diy+transistor&rlz=1C1CHBF_enNZ834NZ839&oq=jeri+ellsworth+diy+transistor&aqs=chrome..69i57j33i160.1989j0j15&sourceid=chrome&ie=UTF-8) - utterly awesome – Russell McMahon Jul 31 '21 at 12:31

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"Powdered" anything means amorphous. Amorphous means not crystalline. Not crystalline means no clearly defined band structure. No clearly defined band structure means no semiconductor behavior. No semiconductor behavior especially means no transistor.

You need a chemical/physical step that forms a periodic potential structure to get something like a semiconductor. So, growth of oxide crystals on an old razor blade works, taking that oxide as powder does not.

So, anything you can print easily won't work, sorry.

You can make transistors at home, but it will tend to look more like Sam Zeloofs Garage than like a slightly modified iinkjet:

chemicals in Sam Zeloof's home lab

mmmm
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  • Interesting, when I was experimenting with geopolymers I needed amorphous SiO2 sand, I guess it just goes to show how unrelated projects can overlap in knowledge learning. Thanks for the feedback, pretty amazing what Sam did, but that's a bit out of my price range. – Questionable Jul 25 '21 at 02:52
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    @mmmm, Stanford Ovshinsky might argue with you if he were still alive. However, he did pioneer the use of amorphous semiconductors. – Kartman Jul 25 '21 at 05:21
  • Amorphous silicon is a semiconductor. Its commonly used to make solar cells for example. – Matt Jul 25 '21 at 16:13
  • @Matt it is my understanding that while you're right, it's a pretty bad one, largely due to very low charge carrier mobility, which would mean you especially can't sensibly inject those into a junction (to build a BJT). – mmmm Jul 25 '21 at 23:02