Far-UV Annealed Inkjet-Printed In₂O₃ Semiconductor Layers for Thin-Film Transistors on a Flexible Polyethylene...

Area of Science:

• Materials Science
• Electronics Engineering
• Nanotechnology

Background:

• Inkjet printing offers a low-cost, scalable method for fabricating electronic devices.
• Developing efficient low-temperature processes for metal oxide semiconductor fabrication on flexible substrates is crucial for next-generation electronics.

Purpose of the Study:

• To optimize an inkjet-printing process for indium oxide (In2O3) precursor solutions.
• To develop a low-temperature conversion method for In2O3 films suitable for flexible substrates.
• To fabricate and characterize enhancement-mode thin-film transistors (TFTs) using the developed process.

Main Methods:

• Optimized precursor solution formulation using ethylene glycol as a cosolvent for stable droplet formation.
• Low-temperature (150-200 °C) conversion of inkjet-printed In2O3 precursor films using combined far-ultraviolet (FUV) exposure and thermal treatment.
• Material characterization using grazing incidence X-ray diffraction (GIXRD), X-ray reflectivity (XRR), and Fourier transform infrared (FTIR) spectroscopy.
• Fabrication and electrical performance evaluation of TFTs on rigid and flexible substrates.

Main Results:

• Achieved a robust and repeatable inkjet-printing process for In2O3 precursor solutions.
• Obtained amorphous, high-density (up to 5.87 g/cm3), and low-impurity In2O3 films via combined FUV and thermal annealing.
• Demonstrated enhancement-mode TFTs with saturation mobilities of 4.3 cm2/(Vs) on rigid Si/SiO2 and ~1 cm2/(Vs) on flexible PEN substrates after 180 min annealing at 150 °C.

Conclusions:

• The developed low-temperature inkjet-printing and annealing process enables the fabrication of high-performance In2O3 semiconductor films on flexible substrates.
• This approach paves the way for manufacturing printed metal-oxide TFT arrays on cost-effective, flexible materials for commercial applications.
• The optimized process offers a promising route for scalable production of flexible electronics.