Flexible Transparent Field-Effect Diodes Fabricated at Low-Temperature with All
Oxide Materials
Yonghui Zhang, Zengxia Mei*, Shujuan Cui, Huili Liang, Yaoping Liu and Xiaolong Du*
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese
Academy of Sciences, Beijing 100190, P. R. China
Contact e-mail:
Flexible transparent circuits have received more and more attention due to their
tremendous applications in flexible displays, wearable human-machine interfacing devices,
remote real-time health monitoring, implantable prosthetics, and multifunctional smart skins
etc. To realize flexible circuits, flexible thin-film diodes (TFDs) are one kind of indispensable
components similar to thin-film transistors (TFTs). In contrast to the remarkable progress
made in flexible oxide TFTs during the last decade, very limited researches have been
revealed on flexible oxide TFD, because most oxide semiconductors are n-type conductive
and own large electron affinity (χ). In that case, it is hard to fabricate high-performance p-n or
Schottky junction diodes based on these materials.
Resolving this crucial issue, we report flexible and fully transparent diodes fabricated at
low temperature (< 100 °C), with a high rectification ratio (~5 × 10
8
) and low leakage current
(~10
-13
A). The device is optically transparent with a transmittance over 80% in visible
spectra range and mechanically robust while bending up to r = 8 mm. Distinguished from
other junction diodes, these diodes utilize a novel diode-connected thin-film transistor
architecture, and field effect plays an important role in the operation principle. A device
physics simulation was employed to illustrate their working mechanism. It was found that
conductive channel was formed under positive bias, while turned off under negative bias.
Finally, single-stage rectifier was successfully built and tested to demonstrate their
applicability on rectification of alternating current (AC) signals at various amplitudes and
frequencies. We believe that this flexible transparent TFD will interest a wide range of
researchers who focus on energy harvest system, radio frequency identification (RFID), one
diode-one resistor (1D1R) memory and flexible or transparent circuits.
Figure Current-voltage (I-V) characteristics of field-effect diode. Inserts show the
schematic and actual picture of the device.
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