High performance solution-processed thin-film transistors based on In ₂O ₃ nanocrystals

Metal-oxide semiconductors have received a great deal of focus in recent years as a means of realizing transparent electronics for next generation display applications; such materials are expected to enable the realization of transparent pixel transistors for display that do not block light, enabling realization of brighter displays with higher aperture ratio. In recent years, the demonstration of amorphous thin films of transition metal oxides with mobility an order of magnitude greater than that of amorphous silicon has resulted in dramatic interest and rapid advances in the field [1]. In particular, solution processable routes are considered particularly attractive since they may allow for low-cost fabrication techniques based on printing. There have been various reports of sol-gel based approaches to printable electronics based on these systems [2-4]; however, an approach utilizing colloidal semiconductor nanocrystals has several distinct advantages. First, the high temperature required for crystal nucleation and growth can occur during the synthesis phase, thus decoupling the high temperature crystallization step from the processing constraints of the substrate. Second, and possibly even more importantly, using nanocrystals as the starting point for inorganic semiconducting inks may provide better control over the stoichiometry of the material, more consistent film composition, and a pathway towards controlled doping of the channel material. Here we report a synthesis of indium oxide nanocrystals, and the fabrication conditions that result in high-performance TFTs based on the same.