All-Inorganic Field Effect Transistors Fabricated by Printing

A solution of cadmium selenide nanocrystals was used to print inorganic thin-film transistors with field effect mobilities up to 1 square centimeter per volt second. This mobility is an order of magnitude larger than those reported for printed organic transistors. A field effect was achieved by developing a synthesis that yielded discretely sized nanocrystals less than 2 nanometers in size, which were free of intimately bound organic capping groups. The resulting nanocrystal solution exhibited low-temperature grain growth, which formed single crystal areas encompassing hundreds of nanocrystals. This process suggests a route to inexpensive, all-printed, high-quality inorganic logic on plastic substrates.