Browsing by Author "Chang, Yu-Cheng"

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A 3D Index (Delta X-3D) for Evaluating Image Quality of Stereoscopic Displays
(2015-10-01)
Chang, Yu-Cheng
;
Chien, Yu-Yi
;
Huang, Yi-Pai
;
光電工程學系
;
Department of Photonics
In stereoscopic displays, crosstalk is typically observed when the views for both eyes are not clearly separated. Crosstalk affects the quality of 3D images and can cause visual fatigue in observers. According to the results of perception experimentation, different visual depth (disparity) and motion blur can also affect the perception of 3D image quality. Therefore, considering the effects of crosstalk, disparity, and motion blur, we propose an evaluation index to quantify 3D image performance for stereoscopic displays. This index assesses the optical quality of a 3D display as well as the effects of image content. According to human vision experimentation, the 3D image index (Delta X-3D) is validated to have a high positive correlation (0.8) with human perception. After combining the human visual mechanism and Delta X-3D, the proposed index can represent the visual quality of static and dynamic images on stereoscopic displays.
A strategy to design highly efficient porphyrin sensitizers for dye-sensitized solar cells
(2011)
Chang, Yu-Cheng
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Wang, Chin-Li
;
Pan, Tsung-Yu
;
Hong, Shang-Hao
;
Lan, Chi-Ming
We designed highly efficient porphyrin sensitizers with two phenyl groups at meso-positions of the macrocycle bearing two ortho-substituted long alkoxyl chains for dye-sensitized solar cells; the ortho-substituted devices exhibit significantly enhanced photovoltaic performances with the best porphyrin, LD14, showing J(SC) = 19.167 mA cm(-2), V(OC) = 0.736 V, FF = 0.711, and overall power conversion efficiency eta = 10.17%.
Analysis of microbial diversity and optimal conditions for enhanced biogas production from swine waste anaerobic digestion
(2013-09-01)
Chung, Ying-Chien
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Chang, Yu-Cheng
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Chen, Yu-Pei
;
Lin, Wei-Chih
;
Lin, Hsiao-Hsien
Swine wastewater pretreated by solid-liquid separation was optimized for biogas production and water purification. Dynamic diversity of the bacterial community in the anaerobic plug flow reactor was investigated under various temperatures and hydraulic retention times (HRT). Results of batch experiments indicated that under optimal operating conditions, biogas production, methane production rate, and chemical oxygen demand (COD) removal efficiencies increased up to 26%, 52%, and 44%, respectively. In the continuous experiments, optimal operating conditions for the plug flow operator were found to be HRT of 8 d and temperature of 35 degrees C, under which relatively high CH4 concentration (67%), CH4 production rate (4.6 l/d), and total COD removal (79%) were achieved. A minimum of 12 bands was observed in the denaturing gradient gel electrophoresis profile. Phylogenetic analysis revealed the predominance of phyla Firmicutes, Proteobacteria, and Euryarchaeota in the anaerobic plug-flow reactor. However, the occurrence and prevalence of specific bacterial species varied with HRT and temperature. This study establishes the optimal operating parameters for the anaerobic plug-flow digestion of swine wastewater, which can be employed in a full-scale reactor to maximize biogas production and to purify water quality. (C) 2013 AIP Publishing LLC.
Aptamer based surface enhanced Raman scattering detection of adenosine using various core sizes of Au-Ag core-shell nanoparticles
(2014-01-01)
Ko, Fu-Hsiang
;
Chang, Yu-Cheng
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The present study synthesizes different sizes of Au nanoparticles (NPs) by adjusting the concentration of citrate. This method produces Au NPs with uniform sizes that can be used to grow Au-Ag core-shell NPs by the seeding growth method. We report the fabrication of monolayer Au NPs or Au-Ag core-shell NPs through the self-assembly of NPs on a 3-aminopropyltrimethoxysilane (APTMS)-modified silicon substrate. The results indicate that the self-assembly time of Au NPs or Au-Ag core-shell NPs plays a crucial role in determining the surface coverage of NPs on the silicon substrate. The appropriate sizes of Au NPs or Au-Ag core-shell NPs were optimized to yield the greatest SERS effect in the rhodamine B molecule. The substrates with self-assembled Au-Ag core-shell NPs can also be used to detect adenosine by a structure-switch aptamer. The combination of Au-Ag core-shell NPs and DNA-based adenosine sensors provides a facile, high enhancement, low detection limit (0.1 nM) and low cost fabrication, which shall be of significant value for practical applications of other aptamer sensing systems.
Aptamer based surface enhanced Raman scattering detection of adenosine using various core sizes of Au-Ag core-shell nanoparticles
(2014-01-01)
Ko, Fu-Hsiang
;
Chang, Yu-Cheng
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The present study synthesizes different sizes of Au nanoparticles (NPs) by adjusting the concentration of citrate. This method produces Au NPs with uniform sizes that can be used to grow Au-Ag core-shell NPs by the seeding growth method. We report the fabrication of monolayer Au NPs or Au-Ag core-shell NPs through the self-assembly of NPs on a 3-aminopropyltrimethoxysilane (APTMS)-modified silicon substrate. The results indicate that the self-assembly time of Au NPs or Au-Ag core-shell NPs plays a crucial role in determining the surface coverage of NPs on the silicon substrate. The appropriate sizes of Au NPs or Au-Ag core-shell NPs were optimized to yield the greatest SERS effect in the rhodamine B molecule. The substrates with self-assembled Au-Ag core-shell NPs can also be used to detect adenosine by a structure-switch aptamer. The combination of Au-Ag core-shell NPs and DNA-based adenosine sensors provides a facile, high enhancement, low detection limit (0.1 nM) and low cost fabrication, which shall be of significant value for practical applications of other aptamer sensing systems.
Au-Ag core-shell nanoparticles with controllable shell thicknesses for the detection of adenosine by surface enhanced Raman scattering
(2015-05-01)
Ko, Fu-Hsiang
;
Tai, Ming-Rou
;
Liu, Fu-Ken
;
Chang, Yu-Cheng
;
材料科學與工程學系
In this study, we report a feasible aqueous chemical method to synthesize Au core-Ag shell nanoparticles (NPs) by seeding growth approach. The concentration of Au NPs plays an important role in growing the different thicknesses of Ag shells. The design of signaling aptamer utilizes the target-induced switching between an aptamer/DNA duplex and an aptamer/target complex. The surface enhanced Raman scattering (SERS) signal was enhanced upon the hybridization of the Raman reporter-labeled DNA released from the target-induced displacement with the captured DNA immobilized on the silicon substrate with Au-Ag core-shell NPs. This substrate with 12.4 nm Ag shell shows high reproducibility, strong enhancement, and a low detection limit (1 nM). The enhancement in DNA-based adenosine detection properties shall be advantageous in applications for other aptamer sensing systems. (C) 2015 Elsevier B.V. All rights reserved.
Characterisation of electron transport and charge recombination using temporally resolved and frequency-domain techniques for dye-sensitised solar cells
(2012)
Li, Lu-Lin
;
Chang, Yu-Cheng
;
Wu, Hui-Ping
;
Diau, Eric Wei-Guang
;
應用化學系
We review systematically the kinetic characterisation of electron transport and charge recombination in dye-sensitised solar cells (DSSC) using both temporally resolved and frequency-domain techniques. For the temporally resolved approach, charge extraction (CE), transient-photocurrent decay (TCD) and transient-photovoltage decay (TVD) methods are introduced in detail; for the frequency-domain approach, techniques involving electrochemical impedance spectroscopy (EIS), intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated photovoltage spectroscopy (IMVS) are presented in detail. The TCD and TVD data are obtained under short-circuit and open-circuit conditions, respectively, and the electron diffusion coefficients and electron lifetimes are extracted from fitting the decay curves accordingly; the IMPS/IMVS results are the counterparts of the TCD/TVD results in the frequency domain. Even though the EIS results are readily acquired, an accurate interpretation of the data requires an appropriate model to determine the internal features of the device. This review provides an account of each technique about its operating principle, experimental setup and data analysis. As case studies for each technique, examples are given to rationalise the observed potential shift, decay coefficients of electron transport and of charge recombination in relation to the corresponding photovoltaic performance of the device.
Compact and High Resolution Virtual Mouse Using Lens Array and Light Sensor
(2016-01-01)
Qin, Zong
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Chang, Yu-Cheng
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Su, Yu-Jie
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Huang, Yi-Pai
;
Shieh, Han-Ping David
Virtual mouse based on IR source, lens array and light sensor was designed and implemented. Optical architecture including lens amount, lens pitch, baseline length, sensor length, lens-sensor gap, focal length etc. was carefully designed to achieve low detective error, high resolution, and simultaneously, compact system volume. System volume is 3.1mm (thickness) x 4.5mm (length) x 2, which is much smaller than that of camera-based device. Relative detective error of 0.41mm and minimum resolution of 26ppi were verified in experiments, so that it can replace conventional touchpad/touchscreen. If system thickness is eased to 20mm, resolution higher than 200ppi can be achieved to replace real mouse.
Control of active semiconducting layer packing in organic thin film transistors through synthetic tailoring of dielectric materials
(2014-01-01)
Singh, Ranjodh
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Meena, Jagan Singh
;
Chang, Yu-Cheng
;
Wua, Chung-Shu
;
Ko, Fu-Hsiang
Apart from the development of new dielectric and semiconductor materials, the semiconductor-dielectric interface study is also very important for the optimum performance of organic thin film transistors (OTFTs). Herein, we have reported the detailed synthesis of a whole new family of dielectric materials which are 1,3,5,7-tetrabromoadamantane; 1,3,5,7-tetrachloroadamanatane; 1,3,5,7-tetraiodoadamantane and 1,3,5,7-tetrauraciladamantane (AdUr(4)). The unique ability of these molecules to undergo supramolecular thin film formation at low temperature, was analysed for their potential use as an insulator in organic electronic devices. Owing to the good leakage current density property shown by AdUr4 dielectric material it was further employed as a gate dielectric in regioregular poly(3-hexylthiophene), (P3HT) based OTFT. This OTFT device which was fabricated on a flexible PI plastic substrate has shown a good on/off current ratio (e.g., 2.18 x 10(4)) and high mobility (e.g., 0.15 cm(2) V-1 s(-1)). The semiconductor-dielectric interface study, has revealed that the AdUr(4) gate dielectric layer has guided the P3HT molecular chain domains to undergo edge-on orientation, which is the charge transport direction in OTFTs. In this process, the grazing incidence X-ray diffraction (GI-XRD) analysis and AFM study was also employed.
Control of active semiconducting layer packing in organic thin film transistors through synthetic tailoring of dielectric materials
(2014-01-01)
Singh, Ranjodh
;
Meena, Jagan Singh
;
Chang, Yu-Cheng
;
Wua, Chung-Shu
;
Ko, Fu-Hsiang
Apart from the development of new dielectric and semiconductor materials, the semiconductor-dielectric interface study is also very important for the optimum performance of organic thin film transistors (OTFTs). Herein, we have reported the detailed synthesis of a whole new family of dielectric materials which are 1,3,5,7-tetrabromoadamantane; 1,3,5,7-tetrachloroadamanatane; 1,3,5,7-tetraiodoadamantane and 1,3,5,7-tetrauraciladamantane (AdUr(4)). The unique ability of these molecules to undergo supramolecular thin film formation at low temperature, was analysed for their potential use as an insulator in organic electronic devices. Owing to the good leakage current density property shown by AdUr4 dielectric material it was further employed as a gate dielectric in regioregular poly(3-hexylthiophene), (P3HT) based OTFT. This OTFT device which was fabricated on a flexible PI plastic substrate has shown a good on/off current ratio (e.g., 2.18 x 10(4)) and high mobility (e.g., 0.15 cm(2) V-1 s(-1)). The semiconductor-dielectric interface study, has revealed that the AdUr(4) gate dielectric layer has guided the P3HT molecular chain domains to undergo edge-on orientation, which is the charge transport direction in OTFTs. In this process, the grazing incidence X-ray diffraction (GI-XRD) analysis and AFM study was also employed.
Controlled Growth Density and Patterning of Silica Nanorings and Nanowires with Enhanced Ultraviolet Cathodoluminescence Peak
(2012-09-01)
Chang, Tung-Hao
;
Lai, Yuan-Chun
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Chang, Yu-Cheng
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Ko, Fu-Hsiang
;
Liu, Fu-Ken
This study reports the use of monodisperse Au nanoparticles (NPs) as a catalyst for growing silica nanorings (NRs) and nanowires (NWs). Combining spin coating and optical lithography strategies makes it possible to fabricate pattern-monolayer Au NPs that self-assemble on a 3-aminopropyltrimethoxysilane (APTMS)-modified silicon substrate. This can be used as a catalyst for the selective-area growth of silica NRs and NWs. Cathodoluminescence (CL) analysis reveals these NRs and NWs materials exhibit a blue-light emitting phenomenon. The novel optical properties of these materials are advantageous in applications for light-emitting devices with nanoscale dimensions.
Creation of 3D Textured Graphene/Si Schottky Junction Photocathode for Enhanced Photo-Electrochemical Efficiency and Stability
(2019-08-01)
Ku, Che-Kuei
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Wu, Po-Hsieh
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Chung, Cheng-Chu
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Chen, Chun-Chi
;
Tsai, Kaijie
This work presents a novel photo-electrochemical architecture based on the 3D pyramid-like graphene/p-Si Schottky junctions. Overcoming the conventional transfer technique by which only planar graphene/Si Schottky junctions are currently available, this work demonstrates the 3D pyramid-like graphene/p-Si Schottky junction photocathode, which greatly enhances light harvesting efficiency and exhibits promising photo-electrochemical performance for hydrogen generation. The formation of 3D pyramid-like graphene/p-Si Schottky junctions exhibits enhanced electrochemical activity and promotes charge separation efficiency compared with the bare pyramid Si surface without graphene. The inherent chemical inertness of graphene significantly improves the operational stability of 3D graphene/p-Si Schottky junction photo-electrochemical cells. The 3D pyramid-like graphene/p-Si Schottky junction photocathode delivers an onset potential of 0.41 V and a saturated photocurrent density of -32.5 mA cm(-2) at 0 V (vs RHE) with excellent stability comparable to values reported for textured or nanostructured p-Si photocathodes coated with ultrathin oxide layers by the conventional atomic layer deposition technique. These results suggest that the formation of graphene/Si Schottky junctions with a 3D architecture is a promising approach to improve the performance and durability of Si-based photo-electrochemical systems for water splitting or solar-to-fuel conversion.
Cylindrical Liquid Crystal Lenses System for Autostereoscopic 2D/3D Display
(2012)
Chen, Chih-Wei
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Huang, Yi-Pai
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Chang, Yu-Cheng
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Wang, Po-Hao
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Chen, Po-Chuan
The liquid crystal lenses system, which could be electrically controlled easily for autostereoscopic 2D/3D switchable display was proposed. The High-Resistance liquid crystal (HRLC) lens utilized less controlled electrodes and coated a high-resistance layer between the controlled-electrodes was proposed and was used in this paper. Compare with the traditional LC lens, the HR-LC Lens could provide smooth electric-potential distribution within the LC layer under driving status. Hence, the proposed HR-LC Lens had less circuit complexity, low driving voltage, and good optical performance also could be obtained. In addition, combining with the proposed driving method called dual-directional overdriving method, the above method could reduce the switching time by applying large voltage onto cell. Consequently, the total switching time could be further reduced to around 2second. It is believed that the LC lens system has high potential in the future.
Direct View and Projection Switchable Mobile Display
(2009-01-01)
Huang, Hsin-Hsuan
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Chen, Cheng-Huan
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Lai, Yu-Cheng
;
Chang, Yu-Cheng
;
Huang, Yi-Pai
The function of mobile phone becomes more versatile as a personal assistant. In order to make display device optimized for different function of the mobile phone, this paper proposes a display device which can be switched among 2D direct view, 3D direct view and projection modes while using single liquid crystal(LC) panel as image source. The device features a highly collimated backlight unit and polymer dispersed liquid crystal(PDLC) diffuser at the back of the LC panel, and a switchable lenticular array as well as a stretchable projection lens in front. The ray tracing simulation has shown well controlled light path of the backlight module and sufficient image quality of the projection lens while maintaining the compactness of the device for mobile application.
Effect of oxygen plasma on the surface states of ZnO films used to produce thin-film transistors on soft plastic sheets
(2013)
Meena, Jagan Singh
;
Chu, Min-Ching
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Chang, Yu-Cheng
;
You, Hsin-Chiang
;
Singh, Ranjodh
Electronic displays and flexible electronics are poised to significantly impact emerging industries, including displays, energy products, sensors and medical devices, building a market that will significantly grow in the future. The implementation of transparent electronic devices requires the use of material components that could be formed using controlled deposition in the appropriate orientation onto a transparent flexible substrate. Here, we report a simple and efficient means of depositing onto a flexible polyimide (PI) substrate a highly ordered and highly aligned zinc oxide (ZnO) film for use as a carrier transporting and semiconducting layer with controlled surface charge density for thin-film transistor (TFT) applications. The deposition approach is based on the solution-coating of a zinc-acetate suspension under controlled conditions of the spread flow rate, droplet size of the drops, speed limit, and the oxygen (ca. O-2) plasma treatment of the coated film surface on the PI substrate. The plasma surface interactions on the surface states of the ZnO films for various times (ca. 1-5 min) were studied using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Moreover, the effects of O-2 plasma and the subsequent thermal annealing in an O-2 atmosphere at 250 degrees C on the properties of ZnO films were studied for its efficacy in TFT applications in terms of the charge carrier density and the change in the mobility. ZnO thin-film-based TFTs on PI exhibited a very high electron mobility of 22.8 cm(2) V-1 s(-1) at a drain bias of 5 V after treatment with O-2 plasma for 2 min. Furthermore, the plasma treatment for long durations of time caused a reduction in the charge carrier density from 1.58 x 10(19) cm(-3) for the 2 min treatment to 1.13 x 10(17) cm(-3) for the 5 min treatment, and the corresponding electron mobility was changed from 22.8 and 3.1 cm(2) V-1 s(-1) for the treatment times of 2 min and 5 min, respectively. The spin-coating technique used to deposit very thin ZnO films is currently used in microelectronics technology, which helps to ensure that the described ZnO thin-film deposition approach can be implemented in production lines with minimal changes in the fabrication design and in the auxiliary tools used in flexible electronics production.
Electroless Plating Growth Au-Ag Core-Shell Nanoparticles for Surface Enhanced Raman Scattering
(2013-05-01)
Chang, Tung-Hao
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Chang, Yu-Cheng
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Ko, Fu-Hsiang
;
Liu, Fu-Ken
;
材料科學與工程學系
Au core-Ag shell nanoparticles (NPs) have been grown on the silicon substrate with self-assembled well-define Au NPs by electroless plating method. The holding time of spin-coating strategy is a facile method for controlling the densities of Au NPs and treating them as an electrode for selective growth of Ag shell. The volumes of silver nitrate play an important role in growing the different shell thicknesses of Au-Ag core-shell NPs. The appropriate shell thicknesses and the densities of Au-Ag core-shell NPs were optimized to yield the greatest surface-enhanced Raman scattering (SERS) effect in rhodamine B molecule. The combination spin-coating strategy and electroless silver plating provide a facile and low cost fabrication method to prepare the different shell thicknesses and densities of Au-Ag core-shell NPs with high SERS enhancement, which shall be of significant value for practical applications of biosensor systems.
Enhanced light harvesting with pi-conjugated cyclic aromatic hydrocarbons for porphyrin-sensitized solar cells
(2011-05-01)
Wang, Chin-Li
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Chang, Yu-Cheng
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Lan, Chi-Ming
;
Lo, Chen-Fu
;
Diau, Eric Wei-Guang
Zinc porphyrins in a series bearing a phenylethynyl, naphthalenylethynyl, anthracenylethynyl, phenanthrenylethynyl or pyrenylethynyl substituent, denoted LD1, LD2, LD3a, LD3p or LD4, respectively, were prepared as photosensitizers for dye-sensitized solar cells. The overall efficiencies of the corresponding devices show a trend LD4 > LD3p > LD2 > LD3a > LD1. Significantly, LD4 features J(SC)/mA cm(-2) 19.627, V(OC)/V = 0.711, and FF = 0.721, giving an efficiency eta = 10.06% of power conversion. This value is superior to that of a N719-based solar cell fabricated under similar experimental conditions. The remarkable performance of the LD4 cell is rationalized to be due to the broader and more red-shifted spectral feature that makes the IPCE spectrum to cover broadly across the entire visible region, 400-800 nm.
Facile synthetic route to implement a fully bendable organic metal-insulator-semiconductor device on polyimide sheet
(2012-05-01)
Meena, Jagan Singh
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Chu, Min-Ching
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Wu, Chung-Shu
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Liang, Jie-Chian
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Chang, Yu-Cheng
Triblock copolymer surfactant, HO(CH2CH2O)(20)(CH2CH(CH3)O)(70)(CH2CH2O)(20)H (i.e. P123)-based nanocrystalline (nc)-TiO2 thin film had been synthesized on organic flexible polyimide (PI) sheet for their application in organic metal-insulator-semiconductor (MIS) device. The nc-TiO2 film over PI was successfully deposited for the first time by a systematic solution proceeds dip-coating method and by the assistance of triblock copolymer surfactant. The effect of annealing temperature (270 degrees C, 5 h) on the texture, morphology and time-induced hydrophilicity was studied by X-ray diffraction (XRD), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle system, respectively, to examine the chemical composition of the film and the contact angle. The surface morphology of the semiconducting layer of organic pentacene was also investigated by using AFM and XRD, and confirmed that continuous crystalline film growth had occurred on the nc-TiO2 surface over flexible PI sheet. The semiconductor-dielectric interface of pentacene and nc-TiO2 films was characterized by current-voltage and capacitance-voltage measurements. This interface measurement in cross-link MIS structured device yielded a low leakage current density of 8.7 x 10(-12) A cm(-2) at 0 to -5V, maximum capacitance of 102.3 pF at 1 MHz and estimated dielectric constant value of 28.8. Furthermore, assessment of quality study of nc-TiO2 film in real-life flexibility tests for different types of bending settings with high durability (c. a. 30 days) demonstrated a better comprehension of dielectric properties over flexible PI sheet. We expected them to have a keen interest in the scientific study, which could be an alternate opportunity to the excellent dielectric-semiconductor interface at economic and low temperature processing for large-area flexible field-effect transistors and sensors. (C) 2012 Elsevier B. V. All rights reserved.
High-efficiency combustion of natural gas with 21-30% oxygen-enriched air
(2010-09-01)
Wu, Kuo-Kuang
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Chang, Yu-Cheng
;
Chen, Chiun-Hsun
;
Chen, Young-Da
;
機械工程學系
This investigation was aimed at studying the influence of 21-30% oxygen concentration on the heating rate, emissions, temperature distributions, and fuel (natural gas) consumption in the heating and furnace-temperature fixing tests. Increase in the oxygen concentration led to a more rapid heating rate and lesser fuel consumption due to lower levels of the inert gas (N(2)). When the oxygen concentration was increased from 21% to 30%, the heating rate was increased by 53.6% in the heating test and the fuel consumption was reduced by 26.1% in the furnace-temperature fixing test. Higher oxygen concentrations yielded higher flame temperature; hence, the NO(x) emission increased with increasing oxygen concentration. However, the increase of NO(x) emission in the furnace-temperature fixing test was less than that in the heating test. Moreover, the NO(x) emission was more sensitive to the excess oxygen at higher oxygen levels. The CO(2) concentration in the flue gas increased linearly with the oxygen concentration. Additionally, the temperature distributions became progressively nonuniform with increasing oxygen concentration because the convective heat transfer coefficient was altered. (C) 2010 Elsevier Ltd. All rights reserved.
High-Performance ZnO Thin-Film Transistors with Location-Controlled Crystal Grains Fabricated by Low-Temperature Hydrothermal Method
(2012-07-01)
Yang, Po-Yu
;
Wang, Jyh-Liang
;
Tsai, Wei-Chih
;
Chang, Yu-Cheng
;
Wang, Shui-Jinn
In this paper, high-performance bottom-gate (BG) thin-film transistors (TFTs) with zinc oxide (ZnO) artificially location-controlled lateral grain growth have been prepared via low-temperature hydrothermal method. For the proper design of source/drain structure of ZnO/Ti/Pt thin films, the grains can be laterally grown from the under-cut ZnO beneath the Ti/Pt layer. Consequently, the single one vertical grain boundary perpendicular to the current flow will be produced in the channel region as the grown grains from the source/drain both sides are impinged. As compared with the conventional sputtered ZnO BG-TFTs, the proposed location-controlled hydrothermal ZnO BG-TFTs (W/L = 250 mu m/10 mu m) demonstrated the higher field-effect mobility of 6.09 cm(2)/V.s, lower threshold voltage of 3.67 V, higher on/off current ratio above 10(6), and superior current drivability, reflecting the high-quality ZnO thin films with less grain boundary effect in the channel region.