Tin Dioxide Electrolyte-Gated Transistors Working in Depletion and Enhancement Modes

Metal oxide semiconductors are interesting for next-generation flexible and transparent electronics because of their performance and reliability. Tin dioxide (SnO2) is a very promising material that has already found applications in sensing, photovoltaics, optoelectronics, and batteries. In this work, we report on electrolyte-gated, solution-processed polycrystalline SnO2 transistors on both rigid and flexible substrates. For the transistor channel, we used both unpatterned and patterned SnO2 films. Since decreasing the SnO2 area in contact with the electrolyte increases the charge-carrier density, patterned transistors operate in the depletion mode, whereas unpatterned ones operate in the enhancement mode. We also fabricated flexible SnO2 transistors that operate in the enhancement mode that can withstand moderate mechanical bending.