Browsing by Author "Chen, Hsiang"

Now showing 1 - 20 of 27

Antibacterial capability of ZnO-based nanostructures manipulated by flake-coated onto silver wires
(2016)
Huang, Shen-Che
;
Wang, Tze-Ting
;
Lu, Tien-Chang
;
Chen, Hsiang
;
光電工程學系
ZnO nanoscale structures were grown on the silver wire, utilizing the electro-hydrothermal method, which deposited to further grow flake-form with pellicle and floccule status via employing certain characterizations. The analysis reveals that ZnO nanoscale flake-form were successfully coated on Ag wire. Besides, the antibacterial testing of sample with ZnO nanoscale flake-form integrated on the polished silver wire may support future detection platforms.
Characterization of spatial manipulation on ZnO nanocomposites consisting of Au nanoparticles, a graphene layer, and ZnO nanorods
(2018-01-01)
Huang, Shen-Che
;
Lu, Chien-Cheng
;
Su, Wei-Ming
;
Weng, Chen-Yuan
;
Chen, Yi-Cian
Three types of ZnO-based nanocomposites were fabricated consisting of 80-nm Au nanoparticles (NPs), a graphene layer, and ZnO nanorods (NRs). To investigate interactions between the ZnO NRs and Au nanoparticle, multiple material analysis techniques including field-emission scanning electron microscopy (FESEM), surface contact angle measurements, secondary ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopic characterizations were performed. Results indicate that incorporating a graphene layer could block the interaction between the ZnO NRs and the Au NPs. Furthermore, the Raman signal of the Au NPs could be enhanced by inserting a graphene layer on top of the ZnO NRs. Investigation of these graphene-incorporated nanocomposites would be helpful to future studies of the physical properties and Raman analysis of the ZnO-based nanostructure design.
Comparison of ZnO and Ti-doped ZnO sensing membrane applied in electrolyte-insulator-semiconductor structure
(2018-04-15)
Lee, Ming Ling
;
Wang, Jer Chyi
;
Kao, Chyuan Haur
;
Chen, Hsiang
;
Lin, Chan Yu
In this paper, we demonstrate electrolyte-insulator-semiconductor devices for biochemical sensing applications prepared from ZnO and Ti-doped ZnO sensing membranes deposited on Si substrates by radio frequency sputtering. The structural, morphological, and compositional features of these deposited films with multitemperature annealing were studied using X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy, respectively. Sensitivity, linearity, hysteresis, and drift rate were measured to determine the sensing and reliability performance of all fabricated devices. Compared to the ZnO electrolyte-insulator-semiconductor (EIS), the Ti-doped ZnO EIS sensor annealed at 700 degrees C exhibits a higher sensitivity of 57.56 mV/pH, lower hysteresis of 2.79 mV, and lower drift rate of 0.29 mV/h. For Ti-doped ZnO, sensitivities of 3.62 mV/mM and 6.42 mV/mM were obtained for urea and glucose sensing, respectively. The improvements are owing to Ti-doping, which produces a rougher sensing surface, a well-crystallized grain structure, and thinner silicate and SiO2 at the silicon-oxide interface.
Degradation mechanisms of bias stress on nitride-based near-ultraviolet light-emitting diodes in salt water vapor ambient
(2019-10-15)
Chen, Lih-Ren
;
Huang, Shen-Che
;
Chiu, Jo-Lun
;
Lu, Chien-Cheng
;
Su, Wei-Ming
Degradation mechanisms of nitride-based near-ultraviolet (near-UV) light-emitting diodes (LEDs) were systematically analyzed by applying forward- and reverse-bias stresses to them in a salt water vapor ambient. The surface temperature of the forward-bias stress sample was higher than that of the reverse-bias stress sample. The high temperature of the forward-bias stress sample accelerated the chemical reaction of the device structure with salt water vapors and led to faster degradation. Composition analyses of the sample surface and cross-section were conducted to investigate the failure mechanism. The analyses results indicated that the erosion of the indium-tin-oxide layer enhanced the diffusion of the conducting metal into the LED crystal. The proposed method can effectively characterize the quality of near-UV LEDs in a short duration.
Degradation of AlGaInP light emitting diodes under reverse-bias operations in salty water vapor
(2015-08-01)
Chen, Hsiang
;
Chu, Li-Chen
;
Lee, Ming Ling
;
Kang, Nai Chung
;
Shei, Shih-Chang
GaP-based light emitting diodes (LEDs) reliability tests are crucial to further development for high-performance LED lighting technology. In this study, we perform reverse-bias stress tests for LEDs in water vapor and salty water vapor ambient, respectively. The results indicate that salty water vapor can quickly degrade LEDs. To investigate the failure mechanisms, electrical measurements, forward-bias and reverse-bias electroluminescence images, and multiple material analyses have been taken to study the failure mechanism. Results indicate that NaCl clustering solids and atom diffusion may cause deformation of the electrode and enhance the degradation of the LEDs. (c) 2014 Elsevier Ltd. All rights reserved.
Degradation of InGaN/GaN LEDs under Forward-bias Operations in Salty Water Vapor
(2016)
Chen, Hsiang
;
Hsieh, Kun Min
;
He, Yun Yang
;
Chu, Li Chen
;
Lee, Ming Ling
Forward-bias stress in salty water vapor can quickly degrade the InGaN/GaN LEDs. To examine the weakness of the device, electrical, optical, and material analyses and characterizations were performed to investigate the failure mechanism. Corrosion of the electrode and Au atom diffusion might result in damages of the device. Results indicate that forward-bias stress in salty water vapor can quickly influence the material properties, optical behaviors, and electrical characteristics of the LED device.
Effects of N-2 and O-2 annealing on the multianalyte biosensing characteristics of CeO2-based electrolyte-insulator-semiconductor structures
(2014-04-01)
Kao, Chyuan Haur
;
Chen, Hsiang
;
Lee, Ming Ling
;
Liu, Che Chun
;
Ueng, Herng-Yih
A CeO2-based multi-analyte electrolyte-insulator-semiconductor (EIS) biosensor has been fabricated on silicon substrate. To enhance the material quality and sensing performance, annealing treatment in N-2 and O-2 ambient has been incorporated. To examine the annealing effects, material analyses were conducted using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) to identify optimal treatment conditions. Furthermore, sensing performance for various ions of Na+, K+, urea, and glucose has also been tested. Results indicate that the membrane annealed at 800 degrees C in O-2 ambience exhibited a better performance with higher multianalyte sensitivity and a lower drift rate compared with the membrane annealed in N-2 ambience. Oxygen in O-2 ambience may cause stronger reflow and fill in the oxygen vacancy so that the material properties and sensing capability can be improved in O-2 annealing ambience. (C) 2014 Elsevier B.V. All rights reserved.
Fabrication and characterization of cobalt nanoparticles on ZnO nanorods on a polished titanium substrate
(2015-08-01)
Lee, Ming Ling
;
Chen, Hsiang
;
Chen, Chin Pang
;
Chu, Li Chen
;
Wang, Sheng Hsin
Cobalt (Co) nanoparticles (NPs) are spread on ZnO nanorods (NRs) on a polished Ti substrate. To characterize the Co NPs on the ZnO NRs, multiple material analyses including field-emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FIR) spectroscopy and secondary ion mass spectroscopy (SIMS) are carried out to examine the nanocomposite. Results indicate that Co NPs may accuthulate on the top part of ZnO NRs because of their sticky property. The CoNPs/ZnO NRs/Ti nanocomposite shows promise for future ferromagnetic device applications. (c) 2015 Elsevier Ltd. All rights reserved.
Influence of reduced graphene oxide on material, antibacterial, and piezoelectric behaviors of ZnO nanorods on foldable indium tin oxide substrates
(2019-07-01)
Tsai, Yu-Sheng
;
Chen, Yan Yu
;
Xu, Chun Yu
;
Chang, Yu Cheng
;
Tsai, Yang Yang
In this study, zinc oxide nanostructures integrated with reduced graphene oxide (RGO) were fabricated on foldable indium tin oxide substrates. To study the influence of RGO on the material, antibacterial, and piezoelectric properties on the nanostructures, multiple material, antibacterial, and electrical measurements were performed. Results indicate that inserting a RGO layer on the foldable substrate could form nanocylinder ZnO structures, which induced hydrophobicity and better antibacterial properties. Moreover, addition of appropriate RGO into ZnO seed layer may cause the growth of finer ZnO nanorods (NRs) and enhance piezoelectric effects. With stable electrical pulse generative piezoelectric effects and antibacterial properties, ZnO nanostructures with addition of RGO on foldable substrates have potential for future flexible biomedical and electronics applications.
Investigations of Electro-hydrothermally Grown ZnO Nanostructures on Copper Grids
(2017-01-01)
Yu, Tzu-Yi
;
Hung, Chen Hao
;
Lee, Yu Shan
;
Lin, Chia Feng
;
Su, Wei Min
Two types of ZnO nanostructures were electro-hydrothermally deposited on mesh 100 and 200 copper grids. To investigate the nanostructures, multiple material analyses were used to analyze the material properties. FESEM images indicate that nanoflowers/nanorods could be grown on the mesh 100 copper grids while a single layer of ZnO nanorods could be grown on the mesh 200 copper grids. Since the size of the grid holes might influence the chemical reactions during the growth of the nanostructures, all the other material analyzes also reveale1 distinct material characteristics of these two types of nanostructures on the copper grid. Based on the experimental results, modulating the ZnO nanostructure will be helpful for future applications of ZnO nanostructures on copper substrates.
Morphological and crystalline analysis of ZnO/ZnS nanostructures on porous silicon substrate
(2020-08-01)
Tsai, Yu-Sheng
;
Hung, Chen Hao
;
Chan, Wei Lun
;
Tsai, Shang Je
;
Lee, Yu Shan
ZnO/ZnS core-shell nanostructures were successfully synthesized on porous silicon substrates using hydrothermal methods. Multiple morphological and crystalline characterizations were performed on the structures. Results indicate that a uniformly grown ZnS shell with a thickness of around 10 nm could be observed on the cross-section of ZnO/ZnS core-shell structures. Furthermore, different crystalline phases and morphologies could be observed in selected area diffraction patterns between neighboring nanostructures. Material compositional analysis conducted by energy-dispersive X-ray spectroscopy indicate that varied nanostructure element compositions grew perpendicular to the substrate. ZnS/ZnO nanostructures on porous silicon substrates show promise for future optoelectronic and electronic device applications.
Morphological, Material, and Optical Properties of ZnO/ZnS/CNTs Nanocomposites on SiO(2)Substrate
(2020-08-01)
Tsai, Yu Sheng
;
Lin, Xin Dai
;
Chan, Wei Lun
;
Tsai, Shang Che
;
Liao, Wei Jen
Ultraviolet A light (UV-A, 320-400 nm), which is unblockable by sunscreen, requires careful detection for disease avoidance. In this study, we propose a novel photosensing device capable of detecting UV-A. Cancer-causing UV light can be simultaneously monitored with tiny rapid response sensors for a high carrier transition speed. In our research, a multifunctional ZnO/ZnS nanomaterial hybrid-sprinkled carbon nanotube (CNT) was created for the purpose of fabricating a multipurpose, semiconductorbased application. For our research, ZnO nanorods (NRs) were grown by using a facile hydrothermal method on SiO(2)substrate, then vulcanized to form ZnO/ZnS coreshell nanorods, which were sprinkled with carbon nanotubes (CNTs). Results indicate that SiO2/ZnO/ZnS/CNT structures exhibited a stronger conducting current with and without light than those samples without CNTs. Multiple material characterizations of the nanostructures, including of atomic force microscopy (AFM) surface morphology evaluation, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) indicate that CNTs could be successfully spread on top of the ZnO/ZnS coreshell structures. Furthermore, chemical binding properties, material crystallinity, and optical properties were examined by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and photoluminescence (PL). Owing to their compact size, simple fabrication, and low cost, ZnO/ZnS coreshell NRs/CNT/SiO2-based nanocomposites are promising for future industrial optoelectronic applications.
Multianalyte biosensor based on pH-sensitive ZnO electrolyte-insulator-semiconductor structures
(2014-05-14)
Kao, Chyuan Haur
;
Chen, Hsiang
;
Lee, Ming Ling
;
Liu, Che Chun
;
Ueng, Herng-Yih
Multianalyte electrolyte-insulator-semiconductor (EIS) sensors with a ZnO sensing membrane annealed on silicon substrate for use in pH sensing were fabricated. Material analyses were conducted using X-ray diffraction and atomic force microscopy to identify optimal treatment conditions. Sensing performance for various ions of Na+, K+, urea, and glucose was also tested. Results indicate that an EIS sensor with a ZnO membrane annealed at 600 degrees C exhibited good performance with high sensitivity and a low drift rate compared with all other reported ZnO-based pH sensors. Furthermore, based on well-established pH sensing properties, pH-ion-sensitive field-effect transistor sensors have also been developed for use in detecting urea and glucose ions. ZnO-based EIS sensors show promise for future industrial biosensing applications. (C) 2014 AIP Publishing LLC.
Optical and electrical characterization of reverse bias luminescence in InGaN light emitting diodes
(2011)
Chen, Hsiang
;
Kao, Chyuan-Haur
;
Lu, Tien-Chang
;
Shei, Shih-Chang
;
光電工程學系
This study investigates the reliability physics of the reverse bias luminescence (RBL) of InGaN/GaN light emitting diodes. Optical and electrical characterization techniques including surface temperature measurements, 2D X-ray fluorescent element analysis, and 2D electroluminescence (EL) measurements reveal the leakage current distribution and the origin of the reverse bias leakage current. Using these techniques, this study examines the electroluminescence behavior and surface temperature distribution in forward bias and reverse bias conditions. Results show that the reverse bias EL originates from hot electron-induced emission, which in turn is due to the leakage current in the high electric field region caused by metal contact abnormalities. The optical and electrical characterization techniques adopted in this study are a promising screening tool for correlating device failures with fabrication processes.
Optical characterizations and reverse-bias electroluminescence observation for reliability investigations of the InGaN light emitting diode
(2013-01-01)
Chen, Hsiang
;
Yeh, Yih-Min
;
Liao, Chuan Hao
;
Lin, Chun Wei
;
Kao, Chuan-Haur
The reverse-bias operation of the InGaN light-emitting diode (LED) device can reveal device-reliability problems. This study uses optical characterization techniques, including surface temperature measurements, two-dimensional (2D) X-ray fluorescent (XRF) element analysis, 2D electroluminescence (EL) images processed by Matlab, and electrical measurements to visualize the current leakages around the metal contact of the device. Connections between the device performance and the reverse-bias EL current distribution have been established. This paper attributes the origin of the reverse-bias emission to a high electric field caused by weak structures during process variations. Hot electron-induced emissions due to a leakage current may be a mechanism of the reverse-bias emission. Furthermore, reverse-bias stress on the devices is performed on the LED devices to investigate reliability issues. The reverse-bias light emission is relevant to reliability problems because of its combination of optical characterization and electrical performance. These techniques provide a screening tool that will correlate device failures with the fabrication process for future industrial applications. (C) 2012 Elsevier B.V. All rights reserved.
Passivation of yellow luminescence defects in GaN film by annealing and CF(4) plasma treatment
(2011-07-01)
Chen, Hsiang
;
Kao, Chyuan-Haur
;
Chen, Yi-Chen
;
Lo, Hong-Kai
;
Yeh, Yih-Min
In this study, we demonstrated that yellow luminescence (YL) defects can be mitigated with proper annealing or CF(4) plasma treatment. Multiple material analyses, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and surface roughness measurements were performed to investigate improvements in GaN film material properties caused by annealing and CF(4) plasma treatment. Filling vacancies during the annealing process and incorporating fluorine atoms to bond with dangling bonds during the plasma treatment process may lessen YL defects and decrease YL luminescence.
Passivation of yellow luminescence defects in GaN film by annealing and CF4 plasma treatment
(2011-07-01)
Chen, Hsiang
;
Kao, Chyuan-Haur
;
Chen, Yi-Chen
;
Lo, Hong-Kai
;
Yeh, Yih-Min
In this study, we demonstrated that yellow luminescence (YL) defects can be mitigated with proper annealing or CF4 plasma treatment. Multiple material analyses, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and surface roughness measurements were performed to investigate improvements in GaN film material properties caused by annealing and CF4 plasma treatment. Filling vacancies during the annealing process and incorporating fluorine atoms to bond with dangling bonds during the plasma treatment process may lessen YL defects and decrease YL luminescence.
Physical and electrical properties of flash memory devices with nickel oxide(NiO2) charge trapping layer
(2017-06-01)
Lee, Ming Ling
;
Chen, Hsiang
;
Kao, Chyuan Haur
;
Mahanty, Rama Krushna
;
Sung, Wei Kung
In this study, we proposed a metal-oxide high-k-oxide-silicon (MOHOS) memory device using a nickel oxide film as the charge trapping layer, and studied the effect of post-deposition rapid thermal annealing (RTA) on the physical and electrical properties. The physical properties were investigated via multiple material analysis techniques such as X-ray diffraction and atomic force microscopy. The optimal annealing temperature for depositing the charge trapping layer was determined through a thorough investigation of the memory window, program/erase (P/E) cycle, crystalline structure, and material composition. Compared to the as-deposited NiO2 film, a MOHOS-type memory device annealed at 900 degrees C in a nitrogen atmosphere exhibited improved memory characteristics, in terms of a larger window in the capacitance-voltage hysteresis, better data retention (lower charge loss of 11%), faster program and erase cycles, and endurance characteristics (104 P/E cycles) without any significant drift in the flat band voltage. Therefore, the MOHOS memory device with a NiO2 trapping layer is a very promising candidate for future memory device applications. (C) 2017 Elsevier Ltd. All rights reserved.
Reliability Analysis of GaN-based UVLEDs under forward bias operations in salty vapor environment
(2017-01-01)
Huang, Shen-Che
;
Li, Heng
;
Lee, Yu-Shan
;
Hung, Chen-Hao
;
Wang, Shing-Chung
We illustrated the reliability of longer wavelength ultraviolet light-emitting diodes (UVLEDs) in salty vapour environment under manipulation of forward-bias stress via consistent electrical and material characterizations. By manipulating the unprecedented operation in salty vapour ambient, we investigated a series of remarkable findings related to origin of failure behaviours.
Reverse-bias Electroluminescence Observation for Reliability Investigations of the InGaN LED
(2010)
Chen, Hsiang
;
Lu, Tien-Chang
;
交大名義發表
;
National Chiao Tung University
The reverse-bias operation of the InGaN LED device can shed a light on device reliability problems. Our goal is to use noninvasive optical characterization techniques including surface temperature measurements, 2D XRF( X-ray fluorescent) element analysis, and 2D electroluminescence measurements to visualize the leakage current distribution and examine the origin of the reverse-bias leakage current. The origin of the reverse-bias emission is attributed to imperfect metal contact caused by process variation. Hot electron induced emission due to the leakage current should be the mechanism of the reverse-bias emission from the surface defect and the imperfect contact. The light emission was proved to be relevant to reliability problems in terms of the leakage current.