I’ve blogged about the experiments of Nyle Steiner before, but just recently got back to his Spark Bang Buzz website again, and found that he’s added a couple of interesting bits. In particular, he shows how to modify a common Cadmium Sulfide Photocell to act like a field effect transistor. The voltage gain provided is quite small (about 1/10) but the power gain is better and the principle is quite interesting. Check it out.
Mr Steiner’s experiment is wonderful, as are most of the experiments on his pages. You might also be interested in the following page that demonstrates the construction of liquid dielectric zinc tin oxide thin-film transistors from scratch:
http://www.andaquartergetsyoucoffee.com/wp/?page_id=130
–Jim