TY - JOUR
T1 - Far-UV Annealed Inkjet-Printed In2O3 Semiconductor Layers for Thin-Film Transistors on a Flexible Polyethylene Naphthalate Substrate
AU - Leppäniemi, Jaakko
AU - Eiroma, Kim
AU - Majumdar, Himandri
AU - Alastalo, Ari
PY - 2017/3/15
Y1 - 2017/3/15
N2 - The inkjet-printing process of precursor solutions containing In nitrate dissolved in 2-methoxyethanol is optimized using ethylene glycol as a cosolvent that allows the stabilization of the droplet formation, leading to a robust, repeatable printing process. The inkjet-printed precursor films are then converted to In2O3 semiconductors at flexible-substrate-compatible low temperatures (150-200 °C) using combined far-ultraviolet (FUV) exposure at ~160 nm and thermal treatment. The compositional nature of the precursor-to-metal oxide conversion is studied using grazing incidence X-ray diffraction (GIXRD), X-ray reflectivity (XRR), and Fourier transform infrared (FTIR) spectroscopy that indicate that amorphous, high density (up to 5.87 g/cm³), and low impurity In2O3 films can be obtained using the combined annealing technique. Prolonged annealing (180 min) at 150 °C yields enhancement-mode TFTs with saturation mobility of 4.3 cm²/(Vs) and ~1 cm²/(Vs) on rigid Si/SiO2 and flexible plastic PEN substrates, respectively. This paves the way for manufacturing relatively high-performance, printed metal-oxide TFT arrays on cheap, flexible substrate for commercial applications.
AB - The inkjet-printing process of precursor solutions containing In nitrate dissolved in 2-methoxyethanol is optimized using ethylene glycol as a cosolvent that allows the stabilization of the droplet formation, leading to a robust, repeatable printing process. The inkjet-printed precursor films are then converted to In2O3 semiconductors at flexible-substrate-compatible low temperatures (150-200 °C) using combined far-ultraviolet (FUV) exposure at ~160 nm and thermal treatment. The compositional nature of the precursor-to-metal oxide conversion is studied using grazing incidence X-ray diffraction (GIXRD), X-ray reflectivity (XRR), and Fourier transform infrared (FTIR) spectroscopy that indicate that amorphous, high density (up to 5.87 g/cm³), and low impurity In2O3 films can be obtained using the combined annealing technique. Prolonged annealing (180 min) at 150 °C yields enhancement-mode TFTs with saturation mobility of 4.3 cm²/(Vs) and ~1 cm²/(Vs) on rigid Si/SiO2 and flexible plastic PEN substrates, respectively. This paves the way for manufacturing relatively high-performance, printed metal-oxide TFT arrays on cheap, flexible substrate for commercial applications.
KW - inkjet printing
KW - low-temperature annealing
KW - metal oxide
KW - plastic substrate
KW - printed transistor
KW - thin-film transistor
KW - OtaNano
UR - http://www.scopus.com/inward/record.url?scp=85015716108&partnerID=8YFLogxK
U2 - 10.1021/acsami.6b14654
DO - 10.1021/acsami.6b14654
M3 - Article
SN - 1944-8244
VL - 9
SP - 8774
EP - 8782
JO - ACS Applied Materials & Interfaces
JF - ACS Applied Materials & Interfaces
IS - 10
ER -