[cpldcpu]

This lists many transistor patents from oldest to newest.

https://patents.google.com/?q=(H03F3%2f16)&sort=old

The Matare/Welker Patent is missing though

https://patents.google.com/patent/US2673948A/en.541

The entire debate is tiring. It would be better if these reviews would put the actual device physics of the different concepts into context.

Is there any report of a reproduction of the device proposed by Lilienfeld in his patents? If he managed to make functional devices back then, it should be possible today? (Note: Cu2S is not a very well controllable semiconductor...)

Edit:

Gemini Deep Research summary here, its quite informative: https://docs.google.com/document/d/1jE0wQVeWP9Eiybh_C6zMKeZ5...

Also specifically on Cu based TFT: https://docs.google.com/document/d/1_B2x2gBPKgGFVgJyQ0qzPdI4...

From the second document: "The primary obstacle for $Cu_2S$ TFTs is degeneracy. Spontaneous copper vacancies form with negligible energy cost in the sulfur lattice. As a result, stoichiometric $Cu_2S$ is thermodynamically unstable in air, rapidly oxidizing or losing copper to form substoichiometric phases ($Cu_{2-x}S$) with hole concentrations exceeding $10^{20}-10^{21} \text{ cm}^{-3}$."

This explains why there are zero reproductions of Lilienfelds devices. It should be noted that Lilienfeld is one of the inventors of electrolytic capacitors and did therefore know where well how to create extremely thin insulating layers as needed for TFTs. It is not impossible to assume that he could have used other semiconductors (e.g. CdS) with his concept. However, the patents seems to specifically mention Cu2S, which does not yield functional TFTs.