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From Molecular Gallium and Indium Siloxide Precursors to Amorphous Semiconducting Transparent Oxide Layers for Applications in Thin-Film Field-Effect Transistors

Authors

  • Dr. Kerim Samedov,

    1. Institute of Chemistry: Metalorganics and Inorganic Materials, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany), Fax: (+49) 30-314 29732
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  • Dr. Yilmaz Aksu,

    1. Institute of Chemistry: Metalorganics and Inorganic Materials, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany), Fax: (+49) 30-314 29732
    2. Current address: Akdeniz University, Faculty of Engineering, Department of Material Science and Engineering, Dumlupinar Bulvari, 07058 Antalya (Turkey)
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  • Prof. Dr. Matthias Driess

    Corresponding author
    1. Institute of Chemistry: Metalorganics and Inorganic Materials, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany), Fax: (+49) 30-314 29732
    • Institute of Chemistry: Metalorganics and Inorganic Materials, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany), Fax: (+49) 30-314 29732
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Abstract

The syntheses, structural characterization, and thermal degradation of a series of the new indium and gallium siloxide dimers [{Me2In(OSiEt3)}2] (1), [{Me2Ga(OSiEt3)}2] (2), [{Me2In(OSi(OtBu)3)}2] (3), [{Me2Ga(OSi(OtBu)3)}2] (4), and In[OSi(OtBu)3)] (5) is reported. Compounds 14 are readily accessible by facile Brönsted reaction of InMe3 or GaMe3 with the corresponding silanols Et3SiOH and (tBuO)3SiOH, respectively. Compound 5 could be obtained by analogous protolysis of [In{N(SiMe3)2}3] with an excess amount of (tBuO)3SiOH. The suitability of 15 to serve as molecular precursors for low-temperature synthesis of amorphous indium and gallium oxide for electronic applications was probed. Thus their thermal degradation was studied by Thermogravimetric/differential thermogravimetry analysis (TGA/DTG). Compounds 14 were decomposed under dry synthetic air (20 % O2, 80 % N2) at low temperature to yield amorphous indium oxide and gallium oxide particles, respectively. In contrast, thermal degradation of 5 affords amorphous indium silicate. All of these products were analyzed by multiple techniques including powder X-ray diffraction analysis (PXRD), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). Thin-film field-effect transistors (FETs) could be fabricated through spin-coating of silicon-wafers with solutions of 1 in toluene and subsequent calcination under dry synthetic air at 350 °C. These films exhibit very good FET performance with a field-effect mobility of 3.0×10−1 cm2 V−1 s and an on/off current ratio of 108.

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