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Current Variation in ZnO Thin-Film Transistor under Different Annealing Conditions  

Yoo, Dukyean (Department of Electrical and Computer Engineering, Ajou University)
Kim, Hyoungju (Department of Electrical and Computer Engineering, Ajou University)
Kim, Junyeong (Department of Electrical and Computer Engineering, Ajou University)
Jo, Jungyol (Department of Electrical and Computer Engineering, Ajou University)
Publication Information
Journal of the Semiconductor & Display Technology / v.13, no.1, 2014 , pp. 63-66 More about this Journal
Abstract
ZnO is a wide bandgap (3.3 eV) semiconductor with high mobility and good optical transparency. However, off-current characteristics of ZnO thin-film transistor (TFT) need improvements. In this work we studied the variation in ZnO TFT current under different annealing conditions. Annealing usually modifies gas adsorption at grain boundaries of ZnO. When oxygen is adsorbed, electron density decreases due to strong electronegativity of the oxygen, and TFT current decreases as a result. Our experiments showed that current increased after vacuum annealing and decreased after air annealing. We explain that the change of off-current is caused by the desorption and adsorption of oxygen at the grain boundaries.
Keywords
Zinc oxide; Thin-film transistor; Sputtering; Annealing; Oxidizer;
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