Browsing by Author "Huang, Yu-Chih"

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Effect of the Annealing Ambient on the Electrical Characteristics of the Amorphous InGaZnO Thin Film Transistors
(2012-07-01)
Huang, Yu-Chih
;
Yang, Po-Yu
;
Huang, Hau-Yuan
;
Wang, Shui-Jinn
;
Cheng, Huang-Chung
The influence of the thermal annealing on the amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) under different ambient gases has been systematically addressed. The chemical bonding states and transfer characteristics of a-IGZO TFTs show evident dependence on the annealing ambient gas. For the a-IGZO TFTs in the oxygen ambient annealing at 250 degrees C for 30 mins exhibited a maximum field effect mobility (max mu(FE)) of 9.36 cm(2)/V . s, on/off current ratio of 6.12 X 10(10), and a subthreshold slope (SS) of 0.21 V/decade. Respectively, the as-deposited ones without annealing possess a max mu(FE) of 6.61 cm(2)/V . s, on/off current ratio of 4.58 x 10(8), and a SS of 0.46 V/decade. In contrast, the a-IGZO TFTs annealed at 250 degrees C for 30 mins in the nitrogen ambient would be degraded to have a max mu(FE) of 0.18 cm(2)/V . s, on/off current ratio of 2.22 X 10(4), and a SS of 7.37 V/decade, corresponding. It is attributed to the content of the oxygen vacancies, according the x-ray photoelectron spectroscopy (XPS) analyze of the three different samples.
Functionalized Carbon Nanotube Thin Films as the pH Sensing Membranes of Extended-Gate Field-Effect Transistors on the Flexible Substrates
(2014-07-01)
Tsai, Wan-Lin
;
Huang, Bai-Tao
;
Wang, Kuang-Yu
;
Huang, Yu-Chih
;
Yang, Po-Yu
The oxygen-plasma-functionalized carbon nanotube thin films on the flexible substrates as the pH sensing membranes of extended-gate field-effect transistors are proposed for the first time. The carbon nanotubes are ultrasonically sprayed onto the polyimide substrates followed by an oxygen-plasma functionalization. Such oxygen-plasma-treated carbon nanotube thin films (CNTFs) exhibit superior pH sensing characteristics with the sensitivity of 55.7 mV/pH and voltage linearity of 0.9996 in a wide sensing range of pH 1-13. Moreover, the excellent flexibility of carbon nanotube is also demonstrated and the oxygen-plasma-treated CNTFs still maintain the sensitivity of 53.6 mV/pH and voltage linearity of 0.9943 even after five-cycle bending test. These results reveal that the oxygen-plasma-treated CNTFs have great potentials in the practically disposal and wearable biosensor applications.
High-Performance Programmable Metallization Cell Memory With the Pyramid-Structured Electrode
(2013-10-01)
Huang, Yu-Chih
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Tsai, Wan-Lin
;
Chou, Chia-Hsin
;
Wan, Chung-Yun
;
Hsiao, Ching
The pyramid structure fabricated with the potassium hydroxide (KOH) anisotropically etched (100) silicon substrate has been deposited with a copper film as the bottom electrode of the programmable metallization cell (PMC) memory to significantly improve the resistive switching characteristic. As compared with the conventional flat copper electrode, this pyramid-structured electrode exhibited the set/reset voltage as low as 1/0.6 V and superior endurance of 2400 cycles at the set/reset voltages of -5/+3 V for the voltages pulsewidth of 1 mu s. The high performance of this PMC could be attributed to high local electrical fields at the tips of the pyramid structure, resulting in the formation of the narrower conductive filaments that facilitate the lower operation voltage and better endurance.
High-performance resistive switching characteristics of programmable metallization cell with oxidized Cu-Ti electrodes
(2013-09-30)
Huang, Yu-Chih
;
Chou, Chia-Hsin
;
Liao, Chan-Yu
;
Tsai, Wan-Lin
;
Cheng, Huang-Chung
Programmable metallization cell (PMC) memory devices with oxidized Cu-Ti alloy films as the bottom electrodes have been shown to exhibit a superior on/off state current ratio (memory window) of as high as 10(3) and endurance of 3000 cycles as compared to conventional pure copper and unoxidized Cu-Ti alloy electrodes. It was conjectured that the Cu-Ti alloy electrodes could obtain the appropriate amount of copper atoms to format and rupture the conductive filaments in the resistive switching layer. Furthermore, the oxidized Cu-Ti alloys could control the Cu cations from the Cu and Cu2O to the appropriate amountto achieve the most favorable PMC characteristics. (C) 2013 AIP Publishing LLC.
On Gray Labeling for Downlink Non-Orthogonal Multiple Access Without SIC
(2016-09)
Shieh, Shin-Lin
;
Lin, Chia-Hung
;
Huang, Yu-Chih
;
Wang, Chin-Liang
;
傳播研究所
The impact of labeling a multilevel coding scheme with pulse amplitude modulation constellation in downlink non-orthogonal multiple access (NOMA) systems is studied. Particular interest is paid to the case where the strong user\'s receiver does not perform successive interference cancellation (SIC) before decoding its desired message. With judiciously chosen parameters, it was shown in a recent work that the considered scheme can approach the capacity region to within a constant gap. In this letter, analytic and extensive simulation results are given to show that Gray labeling provides better performance than non-Gray labeling and natural labeling for the scheme in terms of the symbol error rate, block error rate, and epsilon-feasible rate. Simulation results also indicate that the performance gap between the case with SIC and that without SIC for Gray labeling can be further bridged, which suggests the possibility of avoiding SIC in downlink NOMA.
Sensitivity Enhancement of Ultraviolet Photodetectors With the Structure of p-NiO/Insulator-SiO2/n-ZnO Nanowires
(2015-08-01)
Li, Yu-Ren
;
Wan, Chung-Yun
;
Chang, Chia-Tsung
;
Huang, Yu-Chih
;
Tsai, Wan-Lin
A high-performance photodetector with the structure of NiO/SiO2/ZnO nanowires has been proposed. The devices with 6-nm-thick SiO2 exhibited a better rectification ratio (J(forward)/J(reverse)) of 246 at +/- 2 V, lower dark current density (J(dark)) of 3.5 x 10(-7) A/cm(2) at a reverse bias of 2 V, and superior ultraviolet (UV) sensitivity (I-UV/I-dark) of 16.23 than those without the SiO2 layer (J(forward)/J(reverse) = 44, Jdark = 4.7x10(-6) A/cm(2), and I-UV/I-dark = 5.5). The improved performance was mainly due to the ultrathin inserted SiO2 layer that builds a barrier height to minimize the transmission probability of low-energy carriers, leading to the enhancement of the UV sensing characteristics.
Superior bipolar resistive switching characteristics of Cu-TiO2 based RRAM cells
(2014)
Huang, Yu-Chih
;
Lin, Huan-Min
;
Cheng, Huang-Chung
;
電機學院
;
電子工程學系及電子研究所
Resistive random access memory (RRAM) cells with Cu-doped TiO2 film between two Pt inert electrodes are produced in this work, and these achieve a lower required programming voltage of -0.7 V and higher endurance of about 1000 cycles at the programming/erasing voltage of -5 V/+ 3 V for the pulse width of 1 mu s, compared with the conventional Pt/TiO2/Cu ones. It is conjectured that the distribution of Cu sources in the Cu-doped TiO2 (TiO2 : Cu) resistive switching film facilitates the formation of sharp and narrow conductive filaments, attributed to the Cu sources near the negative biased Pt electrode were oxidised more easily to become the Cu cations than those in other regions. The proposed Pt/TiO2 : Cu/Pt sample can thus achieve a lower DC programming voltage than the conventional one. Moreover, it is conjectured that the better endurance of the Pt/TiO2 : Cu/Pt sample is due to the lower amount of residual Cu atoms in the TiO2 layer from the ruptured filaments during the erasing process. This is because the increase in the amount of Cu atoms is limited by the inert Pt electrode when there are uniformly distributed Cu sources and there is no Cu electrode.
Superior Resistive Switching Characteristics of Cu-TiO2 Based RRAM Cell
(2013)
Huang, Yu-Chih
;
Lin, Huan-Min
;
Cheng, Huang-Chung
;
電機學院
;
電子工程學系及電子研究所
The random access memory (RRAM) cells consisted with the Cu doped TiO2 film and both Pt inert electrodes has been purposed. Compared with the common conductive-bridging mode sample structure which have a Cu active electrode, a non-doped TiO2 film and a Pt inert electrode. "The Cu doped film with both inert electrodes sample exhibited the endurance of 1000 cycles more than the common ones of 400 cycles under the same operating conditions. Furthermore, the doped sample required lower setting voltage of -0.7V than the common ones of -1.5V. The differences in resistance resistive switching characteristics were possible caused by the amounts of Cu ions distribution and the forming of the conductive filaments in the TiO2 layers, according the results of the electrical characteristics measurements and the material analysis.
Thickness effect of NiO on the performance of ultraviolet sensors with p-NiO/n-ZnO nanowire heterojunction structure
(2015-08-01)
Li, Yu-Ren
;
Wan, Chung-Yun
;
Chang, Chia-Tsung
;
Tsai, Wan-Lin
;
Huang, Yu-Chih
Based on the p-NiO/n-ZnO nanowire (NW) heterojunction structure, a high-performance ultraviolet (UV) sensor has been achieved in this work. The sputtered p-type NiO exhibited good coverage on the hydrothermally-grown n-type ZnO Nano-Wires (NW\'s). The devices with 250-nm-thick NiO obtained the highest UV light sensitivity (I-UV/I-Dark = 4.98; I-Visible/I-Dark = 3.82 biased at -2 V) under UV (lambda = 365 nm) intensity as low as 300 mu W/cm(2). Such p-n junction with thinner or thicker NiO layer led to worse UV detecting characteristics due to the fully-depleted NiO layer and larger series resistance, respectively. Furthermore, the N-2 annealing process can increase the UV light response and suppress the visible light response because of the reduced structural defects in ZnO NWs and the fewer interfacial defects (I-UV/I-Dark = 5.65; I-Visible/I-Dark = 1.35 biased at -2 V). (c) 2015 Elsevier Ltd. All rights reserved.