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

Abstract

Metal oxide semiconductors are interesting for next-generation flexible and transparent electronics because of their performance and reliability. Tin dioxide (SnO) 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 SnO transistors on both rigid and flexible substrates. For the transistor channel, we used both unpatterned and patterned SnO films. Since decreasing the SnO 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 SnO transistors that operate in the enhancement mode that can withstand moderate mechanical bending.

Combining Aqueous Solution Processing and Printing for Fabrication of Flexible and Sustainable Tin Dioxide Ion‐Gated Transistors

“…The performances of our flexible transistor measurements are comparable with those of flexible SnO 2 FETs and IGTs reported in the literature. [ 13,19 ] The electrical characteristics of the IGTs at different scan rates (10 and 100 mV s −1 ) do not show significant differences (Figures S7 and S8, Supporting Information), likely because the rate of doping/dedoping of SnO 2 films is not affected by the scan rate within the investigated range of rates. Transfer curves measured with 10 repetitive cycles in linear and saturation region show good operational stability (Figure S9, Supporting Information), with no significant change in device characteristics.…”

“…Prior to use, [EMIM] [TFSI] was purified at 60 °C for overnight under vacuum (≈10 −5 Torr). [19] For aqueous electrolyte gating, the aqueous gating medium, that is, 0.1 m NaCl, was confined using a PDMS well or a cellulose (9 × 4 mm) filter soaked with 0.1 m aqueous NaCl solution and placed on the top of the patterned electrodes. To complete the device fabrication, an activated carbon gate electrode was placed on top of cellulose filter.…”

“…[25] Our research group fabricated solutionprocessed SnO 2 films with a processing temperature of 350 °C and demonstrated ionic liquid-based IGTs on flexible substrates, which were stable up to a moderate bending. [19] In this work we synthesized SnO 2 films on thin, flexible polyethylene terephthalate (PET) substrates using an environmentally sustainable aqueous growth at the maximum processing temperature of 95 °C. The controlled aqueous growth is a suitable technique to deposit SnO 2 nanorods on crystalline or amorphous substrates using an acidic growth solution at low temperatures (95 °C).…”

Progress Report on “From Printed Electrolyte‐Gated Metal‐Oxide Devices to Circuits”

“…The setup time of the D Flip Flop is less than 50 ms and the operation frequency is only around 5 Hz, however this example shows the potential of EGFETs for the use in complex circuits. [15,27,28] Single crystal oxide semiconductors, for instance, typically show the highest carrier mobility values, in the case of indium oxide specifically in the range of several 100 cm 2 V −1 s −1 . [26] The retention time of the DRAM cell is greater than 1 min when the write pulse is 20 ms long.…”

“…Owing to their high mobility values, solution processed oxide semiconductors like indium oxide, indium gallium zinc oxide, and zinc oxide have recently become popular as channel material in printed FET technology. [15,27,28] Single crystal oxide semiconductors, for instance, typically show the highest carrier mobility values, in the case of indium oxide specifically in the range of several 100 cm 2 V −1 s −1 . [15,29] Other favorable properties of these wide bandgap oxide semiconductors include stability in air over a wide temperature range, optical transperency, mechanical flexability, and their abilitiy to be easily processable in printing techniques.…”