Browsing by Author "Chen, Yi-Jung"

Now showing 1 - 5 of 5

Factors Affecting Hysteresis in the Transfer Curves of a-IGZO TFTs under Illumination and Raised Temperature
(2015)
Chen, Yi-Jung
;
Tai, Ya-Hsiang
;
光電工程學系
;
顯示科技研究所
;
Department of Photonics
For different environments of illumination and temperature, we investigate the hysteresis in the transfer characteristic of a-IGZO TFT by controlling the sweep speed of the gate voltage. The hysteresis can be affected by the response time for the transition of oxygen vacancies states to the ionized states and its amount.
Hysteresis of Transistor Characteristics of Amorphous IGZO TFTs Studied by Controlling Measurement Speed
(2015-01-01)
Chen, Yi-Jung
;
Tai, Ya-Hsiang
;
光電工程學系
;
顯示科技研究所
;
Department of Photonics
We investigate the hysteresis in the transfer characteristic of amorphous indium-gallium-zinc-oxide thin-film transistor by controlling the sweep waveform of the gate voltage (Vg) provided by parameter measure unit. It is conventionally studied by double sweeping Vg with the default setup of the source measure units, which speed may vary with the current level. By manipulating the step time of sweeping Vg, we found that the response time of charge traps or donor-like states is in the range that overlaps with the conventional time step in the measurement and must be considered. (C) The Author(s) 2015. Published by ECS. All rights reserved.
Mechanism of Hysteresis for a-IGZO TFT Studied by Changing the Gate Voltage Waveform in Measurement
(2016-04)
Chen, Yi-Jung
;
Tai, Ya-Hsiang
;
Chang, Chun-Yi
;
光電工程學系
;
Department of Photonics
In this paper, we investigate the response time of oxygen vacancies on the hysteresis for the amorphous indium-gallium-zinc oxide thin-film transistors. The fast pulse measurement method is used to observe the drain current under the different sweeping speeds of gate voltage to clarify the mechanism of the hysteresis. Effects of light intensity and temperature are also discussed. Based on the results and the analysis, the model of oxygen vacancies is proposed to explain the effect of sweep speed on the hysteresis, which would be important for the devices to be driven in their circuit application.
Size effect on multiferroic TbMn2O5 nanorods
(2015-05-07)
Yang, Chun-Chuen
;
Tung, Yung-Hsiang
;
Chen, Yi-Jung
;
Hsu, Ting-Wei
;
You, Pang-Yen
The effect of the size of TbMn2O5 on their magnetoelectric properties is studied using a field emission transmission electron microscope, ac magnetic susceptibility, relative dielectric constant, specific heat capacity, and x-ray diffraction at various temperatures. A bulk sample and nanorods with two axial lengths, < L-C >, are investigated. Nanorods with < L-C > of 216 nm and 64 nm crystallize with orthorhombic Pbam symmetry as the bulk material. The axial direction of the two sizes of nanorod is parallel to the c axis of the crystal. No particular radial direction is observed. The critical size for the magnetic ordering of TbMn2O5 is found to be between < L-C > - 64 nm and 216 nm. Experiments on specific heat capacity verified these results. No similar phenomenon concerning the ferroelectric property is observed. At T = 30K and 35 K, the < L-C > - 216 nm sample yields a charge-ordering-like x-ray diffraction peak, which may be associated with the magnetically induced charge ordering superlattice. (C) 2015 AIP Publishing LLC.
The Time Response of the On-Current for the Amorphous In-Ga-Zn-O Thin Film Transistor to the Illumination Pulse
(2014)
Tai, Ya-Hsiang
;
Chang, Chun-Yi
;
Chen, Ya-Wei
;
Chen, Yi-Jung
;
交大名義發表
In this study, the time response behavior of the amorphous indium gallium zinc oxide (a-IGZO) thin film transistors (TFTs) to the illumination pulse is analyzed. The mechanism is proposed to correlate the oxygen vacancy reacting with the light-induced electron-hole pairs. The temperature effect on the time response to the illumination pulse is also studied. The higher excitation level, either from light or temperature, results in the similar excited and recovering behaviors. The formulas for the time response are proposed to be possibly used in the simulation for the circuit performance in real situation of illumination, which is important in the development of transparent electronics using a-IGZO TFT. (c) The Author(s) 2014. Published by ECS. All rights reserved.