Amorphous In-Ga-Zn-O thin-film transistors fabricated by microcontact printing

Abstract

The authors present a facile, low-cost methodology to fabricate high-performance In-Ga-Zn-O (IGZO) bottom contact, bottom gate thin-film transistors (TFTs) by soft lithography. The IGZO channel and indium tin oxide (ITO) source and drain were patterned using microcontact printing of an octadecylphosphonic acid self-assembled monolayer (SAM). A polymer stamp was used for the pattern transfer of the SAMs, which were then used as a chemical protection layer during wet etching. Excellent pattern transfer was obtained with good resolution and sharp step profiles. X-ray photoelectron spectroscopy indicated that the microcontact printed SAMs can be effectively removed from the ITO source/drain surfaces, allowing a high-quality interface to the IGZO channel for good device performance. Scanning electron microscopy cross-sections of the devices indicate a smooth and defect-free transition regions between the source/drain and semiconductor regions. The fabricated TFTs have negligible gate-leakage currents, high average electron mobilities of 10.2 cm 2 /Vs, and excellent on-off ratios of 2.1 Â 10 8. These results may provide new methodologies for low-cost and large-area integration of IGZO-TFTs for a range of applications including flexible and transparent displays. V

In Situ Chemical Modification of Schottky Barrier in Solution-Processed Zinc Tin Oxide Diode

“…The oxygen-plasma generated PdO x layer provided an oxygen-rich environment during the metal oxide formation of Zn–Sn–O and thus reduced the concentration of oxygen vacancies near the Pd/Zn–Sn–O interface. We note that a different interpretation of the O 1s peaks exists in some studies: − the 531 eV peak is attributed to metal hydroxides (M–OH), with the 532 eV peak attributed to weakly bound water or carbonate species. However, with this interpretation, we find it difficult to understand the observed correlation of the decrease of the 531 eV peak at the interface with the reduction of PdO x .…”

Glucose Sensing Using Functionalized Amorphous In–Ga–Zn–O Field-Effect Transistors

“…Source/drain (S/D) electrodes were patterned using photolithography and etched in diluted HCl (1:20 HCl:H 2 O) giving a width/length ( W / L ) ratio of 100 μm/20 μm. The ITO films were then annealed in air at 300 °C for 1 h to increase their resistance to the HCl etch, increase their electrical conductivity, and improve their transparency . Amorphous IGZO films (∼50 nm thick) were deposited by sputter deposition using a 3 in.…”

Printed Thin-Film Transistors: Research from China

“…Meantime, by adding poly­(4-vinylphenol) (PVP) to adjust the viscosity of inks, a uniform and printed IGZO TFTs array could be fabricated, leading to the highest mobility of about 6.2 cm 2 V –1 s –1 and I on / I off of ∼1 × 0 7 (Figure e). In addition, sensors and detectors based on inkjet-printed compound TFTs have been reported by Du and co-workers as well. , …”

“…Inorganic semiconductor exhibits the advantages of high carrier mobility and excellent air-stability, and several research groups have been focusing on inorganic TFTs. − The printed inorganic TFTs are mainly composed of n -type semiconductors, such as binary (ZnO, In 2 O 3 , SnO 2 , Ga 2 O 3 ), ternary (ZIO, ITO, ZTO, IGO), and quaternary compounds (IZTO, IGZO), as well as some p -type semiconductors including CuI, CuO, NiO, WSe 2 , and CuInSe 2 . ,,, …”

“…In addition, sensors and detectors based on inkjet-printed compound TFTs have been reported by Du and co-workers as well. 121,123 Except for printed inorganic TFTs discussed above, other types of inorganic TFTs fabricated via printing process have attracted much attention as well. Liu et al reported TFTs based on highly ordered horizontally aligned nanowire arrays of Zn 2 GeO 4 and In 2 Ge 2 O 7 by transfer printing technique, which exhibited effective mobility of 25.44 cm 2 V −1 s −1 and 11.9 cm 2 V −1 s −1 , respectively.…”