Browsing by Author "Chang, Chih-hung"

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Fabrication of high-performance, low-temperature solution processed amorphous indium oxide thin-film transistors using a volatile nitrate precursor
(2015-01-01)
Choi, Chang-Ho
;
Han, Seung-Yeol
;
Su, Yu-Wei
;
Fang, Zhen
;
Lin, Liang-Yu
In this study, we fabricate amorphous indium oxide thin film transistors (TFTs) on a display glass substrate at various annealing temperatures from 200 degrees C to 300 degrees C. Using a volatile nitrate precursor, we were able to fabricate TFTs with excellent device performance within this annealing temperature range. Amorphous In2O3 films could be obtained by carefully controlling the film thickness and annealing temperature. TFTs based on amorphous In2O3 channel layers with an average mobility as high as 7.5 cm(2) V-1 s(-1), an I-on/I-off ratio of 10(7), and V-on = -5 V could be fabricated at 300 degrees C annealing temperature in air. The devices prepared at 200 degrees C still exhibit transistor characteristics with an average mobility of 0.04 cm(2) V-1 s(-1), an Ion/Ioff ratio of 10(5), and V-on = 0 V. The temperature effects on the device performances are elucidated based on X-ray photoelectron spectroscopy and thermal gravimetric analysis characterization results of precursors and the resulting amorphous In2O3 thin films.
The effects of gallium on solution-derived indium oxide-based thin film transistors manufactured on display glass
(2015-01-01)
Choi, Chang-Ho
;
Su, Yu-Wei
;
Lin, Liang-Yu
;
Cheng, Chun-Cheng
;
Chang, Chih-hung
Metal oxide semiconductor TFTs have been considerably investigated as a promising alternative to hydrogenated amorphous silicon and organic semiconductors. While many multicomponent oxide TFTs have been studied, there are only a few reports of TFTs using amorphous indium gallium oxide channel layers. In this study, the effects of gallium atomic ratio on the performance of solution-derived indium oxide-based TFTs on display glass were investigated for the first time. The morphological, optical, and electrical properties of IGO channel layers with different gallium atomic ratios were characterized. IGO TFTs with various chemical compositions were compared and interpreted based on the analysis of In3d, Ga2p, and O1s XPS data. It was found that gallium dopant suppresses the generation of oxygen vacancies, while promoting the formation of oxygen in the oxide lattice without oxygen vacancies by reducing the density of hydroxides. By adjusting the atomic ratio of gallium, we were able to fabricate IGO TFTs on display glass with an average field-effect mobility as high as 6.1 cm(2) V-1 s(-1), V-on = -2 V, and on-off ratio of 10(7).