Browsing by Author "Chang, Jung-Fang"

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The suppressed negative bias illumination-induced instability in In-Ga-Zn-O thin film transistors with fringe field structure
(2012-11-26)
Chen, Yu-Chun
;
Chang, Ting-Chang
;
Li, Hung-Wei
;
Hsieh, Tien-Yu
;
Chen, Te-Chih
This study investigates the suppressed negative gate bias illumination stress (NBIS) -induced instability of via-type amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistors (TFTs) with fringe field (FF) structures. The less negative threshold voltage shifts of devices after NBIS are showed when device has larger FF structures. This finding is attributed to more dispersive distribution of photo-generated holes in the width direction of a-IGZO during NBIS, which reduce the hole trapping phenomenon in the front channel interface. The a-IGZO TFT with FF structure is expected to be an effective method to increase the electrical reliability of devices after NBIS. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4767996]
Ultrahigh Sensitivity Self-Amplification Phototransistor Achieved by Automatic Energy Band Lowering Behavior
(2014-09-01)
Chen, Hua-Mao
;
Chang, Ting-Chang
;
Tai, Ya-Hsiang
;
Chen, Yu-Chun
;
Yang, Man-Chun
In this paper, amorphous InGaZnO4 thin-film transistors with an asymmetric structure exhibit ultraviolet (UV) light sensing property. At the offset region near the drain electrode, the extended active layer plays the role of a resistor. However, the ON-state current is obviously reduced with increasing offset length at the offset region near the source electrode and the characteristics cannot be turned ON when offset length is over 4 mu m. After exposure to UV light, photogenerated holes-induce source barrier lowering and then amplifying the photocurrent response. Therefore, the devices in this paper reach a high-ON/OFF ratio of UV sensitivity to 10(6).