Selected Papers from Taiwan Association for Academic Innovation, TAAI 2019

A special issue of Crystals (ISSN 2073-4352).

Deadline for manuscript submissions: closed (30 June 2020) | Viewed by 23301

Special Issue Editors

Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung 40227, Taiwan
Interests: silicon thin-film solar cells; silicon heterojuction solar cells; PV systems design, evaluation, and diagonosis
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Dear Colleagues,

On behalf of the Taiwan Association for Academic Innovation, we are pleased to welcome you to the 3rd IEEE and 4th International Conference on Science, Education, Viable Engineering (ICSEVEN) 2019 on April 6–10, 2019, Ho Chi Minh, Vietnam. (URL: http://www.taai.tw/icseven/).

Following the first ICSEVEN held in Guilin, China; the second in Kyoto, Japan; and the third in Zhengzhou, China, the conference continuously aims to foster the growth of research in energy engineering science and technology and its benefits to the community at large in the future. We hope that ICSEVEN 2019 will provide a great platform for academic and industry professionals to have fruitful discussions and to exchange new ideas about recent developments and the latest advances in the interdisciplinary field. It is our pleasure to announce the supportive participation of leading academics and researchers, in their respective areas of focus, from various countries, not only in but also beyond Asia. We invite you to participate in this conference by submitting a paper reflecting your current research and to excel in solar energy-related R&D worldwide.

Participants of the conference are cordially invited to contribute original research papers or reviews to this Special Issue of Crystals.

Prof. Dr. Chien-Jung Huang
Prof. Dr. Yeu-Long Jiang
Prof. Fei Yu
Guest Editors

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Keywords

  • solar cell and module technology
  • photovoltaics
  • crystallization and wafering of solar energy system
  • new materials for next generation solar cell

Published Papers (7 papers)

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Research

12 pages, 4960 KiB  
Article
Capacitance Characteristics and Breakdown Mechanism of AlGaN/GaN Metal–Semiconductor–Metal Varactors and their Anti-Surge Application
by Chien-Fu Shih, Yu-Li Hsieh, Liann-Be Chang, Ming-Jer Jeng, Zi-Xin Ding and Shao-An Huang
Crystals 2020, 10(4), 292; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst10040292 - 10 Apr 2020
Cited by 2 | Viewed by 2407
Abstract
The AlGaN/GaN materials with a wide band gap, high electron mobility, and high breakdown voltage are suitable for manufacturing high-power and high-frequency electronic devices. In this study, metal Schottky contact electrodes of different dimensions are prepared on AlGaN/GaN wafers to fabricate metal–semiconductor–metal (MSM) [...] Read more.
The AlGaN/GaN materials with a wide band gap, high electron mobility, and high breakdown voltage are suitable for manufacturing high-power and high-frequency electronic devices. In this study, metal Schottky contact electrodes of different dimensions are prepared on AlGaN/GaN wafers to fabricate metal–semiconductor–metal (MSM) varactors. Voltage-dependent capacitance and breakdown voltages of the varactors are measured and studied. The corresponding breakdown mechanisms of varactors with different electrode gaps are proposed. Furthermore, an anti-surge application using GaN-based MSM varactors in a signal transmission module is demonstrated, and its surge suppression capability is shown. We believe that our study will be beneficial in developing surge protection circuits for RF applications. Full article
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10 pages, 14650 KiB  
Article
On the Nitrogen Doping in Erbium and Nitrogen Codoped Magnesium Zinc Oxide Diode by Spray Pyrolysis
by Chun-An Chen, Yu-Ting Hsu, Wen-How Lan, Kai-Feng Huang, Kuo-Jen Chang, Mu-Chun Wang and Chien-Jung Huang
Crystals 2020, 10(1), 34; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst10010034 - 12 Jan 2020
Cited by 3 | Viewed by 2003
Abstract
Diodes with an erbium and nitrogen codoped magnesium zinc oxide (MgZnO:Er,N) active layer were fabricated by spray pyrolysis on Si substrate with aqueous solutions including magnesium nitrate, zinc acetate, erbium acetate, ammonium acetate, and indium nitrate precursors. Diodes with different nitrogen content in [...] Read more.
Diodes with an erbium and nitrogen codoped magnesium zinc oxide (MgZnO:Er,N) active layer were fabricated by spray pyrolysis on Si substrate with aqueous solutions including magnesium nitrate, zinc acetate, erbium acetate, ammonium acetate, and indium nitrate precursors. Diodes with different nitrogen content in their precursor were prepared and their properties were investigated. With scanning electron microscopy, film surface with mixed hexagonal flakes and tiny blocks was characterized for all samples. Certain morphologies varied for samples with different N contents. In the photoluminescence analyses, the intensity of the oxygen-related defects peak increased with the increasing of nitrogen content. The diodes were fabricated with an Au and In deposition on the top and backside. The diode current–voltage as well as capacitance–voltage characteristics were examined. An ununiformed n-type concentration distribution with high concentration near the interface in the MgZnO:Er,N layer was characterized for all samples. Diodes with high nitrogen content exhibit reduced breakdown voltage and higher interface concentration characteristics. Under reversed bias conditions with an injection current of 50 mA, a light spectrum with two distinct green emissions around wavelengths 532 and 553 nm was observed. A small spectrum variation was characterized for diodes prepared from different nitrogen content. The diode luminescence characteristics were examined and the diode prepared from N/Zn=1 in the precursor showed an optimal injection current-to-luminescence property. The current and luminescence properties of the diode were characterized and discussed. Full article
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6 pages, 2232 KiB  
Article
Low Gate Lag Normally-Off p-GaN/AlGaN/GaN High Electron Mobility Transistor with Zirconium Gate Metal
by Chia-Hao Liu, Hsien-Chin Chiu, Chong-Rong Huang, Kuo-Jen Chang, Chih-Tien Chen and Kuang-Po Hsueh
Crystals 2020, 10(1), 25; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst10010025 - 06 Jan 2020
Cited by 4 | Viewed by 4096
Abstract
The impact of gate metal on the leakage current and breakdown voltage of normally-off p-GaN gate high-electron-mobility-transistor (HEMT) with nickel (Ni) and zirconium (Zr) metals were studied and investigated. In this study, a Zr metal as a gate contact to p-GaN/AlGaN/GaN high mobility [...] Read more.
The impact of gate metal on the leakage current and breakdown voltage of normally-off p-GaN gate high-electron-mobility-transistor (HEMT) with nickel (Ni) and zirconium (Zr) metals were studied and investigated. In this study, a Zr metal as a gate contact to p-GaN/AlGaN/GaN high mobility transistor (HEMT) was first applied to improve the hole accumulation at the high gate voltage region. In addition, the ZrN interface is also beneficial for improving the Schottky barrier with low nitrogen vacancy induced traps. The features of Zr are low work function (4.05 eV) and high melting point, which are two key parameters with p-GaN Schottky contact at reversed voltage. Therefore, Zr/p-GaN interface exhibits highly potential for GaN-based switching power device applications. Full article
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5 pages, 919 KiB  
Article
Subthreshold Characteristics of a Metal-Oxide–Semiconductor Field-Effect Transistor with External PVDF Gate Capacitance
by Jing-Jenn Lin, Ji-Hua Tao and You-Lin Wu
Crystals 2019, 9(12), 673; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst9120673 - 14 Dec 2019
Cited by 1 | Viewed by 3597
Abstract
An organic ferroelectric capacitor, using polyvinylidene difluoride (PVDF) as the dielectric, was fabricated. By connecting the PVDF capacitor in series to the gate of a commercially purchased metal-oxide–semiconductor field-effect transistor (MOSFET), drain current (ID)–drain voltage (VD) characteristics [...] Read more.
An organic ferroelectric capacitor, using polyvinylidene difluoride (PVDF) as the dielectric, was fabricated. By connecting the PVDF capacitor in series to the gate of a commercially purchased metal-oxide–semiconductor field-effect transistor (MOSFET), drain current (ID)–drain voltage (VD) characteristics and drain current (ID)–gate voltage (VG) characteristics were measured. In addition, the subthreshold slopes of the MOSFET were determined from the IDVG curves. It was found that the subthreshold slope could be effectively reduced by 23% of its original value when the PVDF capacitor was added to the gate of the MOSFET. Full article
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11 pages, 2338 KiB  
Article
Silicon Heterojunction Solar Cells with p-Type Silicon Carbon Window Layer
by Chia-Hsun Hsu, Xiao-Ying Zhang, Ming Jie Zhao, Hai-Jun Lin, Wen-Zhang Zhu and Shui-Yang Lien
Crystals 2019, 9(8), 402; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst9080402 - 03 Aug 2019
Cited by 15 | Viewed by 5336
Abstract
Boron-doped hydrogenated amorphous silicon carbide (a-SiC:H) thin films are deposited using high frequency 27.12 MHz plasma enhanced chemical vapor deposition system as a window layer of silicon heterojunction (SHJ) solar cells. The CH4 gas flow rate is varied to deposit various a-SiC:H [...] Read more.
Boron-doped hydrogenated amorphous silicon carbide (a-SiC:H) thin films are deposited using high frequency 27.12 MHz plasma enhanced chemical vapor deposition system as a window layer of silicon heterojunction (SHJ) solar cells. The CH4 gas flow rate is varied to deposit various a-SiC:H films, and the optical and electrical properties are investigated. The experimental results show that at the CH4 flow rate of 40 sccm the a-SiC:H has a high band gap of 2.1 eV and reduced absorption coefficients in the whole wavelength region, but the electrical conductivity deteriorates. The technology computer aided design simulation for SHJ devices reveal the band discontinuity at i/p interface when the a-SiC:H films are used. For fabricated SHJ solar cell performance, the highest conversion efficiency of 22.14%, which is 0.33% abs higher than that of conventional hydrogenated amorphous silicon window layer, can be obtained when the intermediate band gap (2 eV) a-SiC:H window layer is used. Full article
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13 pages, 3584 KiB  
Article
Preparation and Characterization of Nanocrystalline TiO2 on Microsericite for High-Efficiency Photo-Energy Conversion of Methanol to Hydrogen
by Chao-Wei Huang, Min-Chien Wu, Van-Huy Nguyen and Ba-Son Nguyen
Crystals 2019, 9(8), 380; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst9080380 - 24 Jul 2019
Cited by 16 | Viewed by 2204
Abstract
TiO2 and TiO2/sericite photocatalysts were successfully synthesized via the sol-gel method by adding a varying amount of acetic acid. The effect of acetic acid on TiO2 and TiO2/sericite photocatalysts was studied. The crystallite size, surface morphology, chemical [...] Read more.
TiO2 and TiO2/sericite photocatalysts were successfully synthesized via the sol-gel method by adding a varying amount of acetic acid. The effect of acetic acid on TiO2 and TiO2/sericite photocatalysts was studied. The crystallite size, surface morphology, chemical composition, specific surface area, surficial functional groups, and light absorbance of the prepared photocatalysts were revealed by the analysis of X-ray diffraction (XRD), scanning electron microscope-energy dispersive spectrometry (SEM-EDS), nitrogen adsorption-desorption isotherms by using BET theory (Brunauer–Emmett–Teller), Fourier-transform infrared spectroscopy (FTIR), and UV-Vis absorption spectrometry. Photo-energy conversion of methanol to hydrogen was also conducted over the prepared photocatalysts. The best hydrogen production was achieved by using the TiO2/sericite photocatalyst to give a hydrogen production rate of 1424 μmol/g·h in 6 h of UV-light irradiation. Full article
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8 pages, 3050 KiB  
Article
Effects of Sm2O3 and V2O5 Film Stacking on Switching Behaviors of Resistive Random Access Memories
by Jian-Yang Lin, Kuang-Yao Wu and Kai-Huang Chen
Crystals 2019, 9(6), 318; https://0-doi-org.brum.beds.ac.uk/10.3390/cryst9060318 - 19 Jun 2019
Cited by 1 | Viewed by 3115
Abstract
In this work, the resistive switching characteristics of resistive random access memories (RRAMs) containing Sm2O3 and V2O5 films were investigated. All the RRAM structures made in this work showed stable resistive switching behavior. The High-Resistance State and [...] Read more.
In this work, the resistive switching characteristics of resistive random access memories (RRAMs) containing Sm2O3 and V2O5 films were investigated. All the RRAM structures made in this work showed stable resistive switching behavior. The High-Resistance State and Low-Resistance State of Resistive memory (RHRS/RLRS) ratio of the RRAM device containing a V2O5/Sm2O3 bilayer is one order of magnitude higher than that of the devices containing a single layer of V2O5 or Sm2O3. We also found that the stacking sequence of the Sm2O3 and V2O5 films in the bilayer structure can affect the switching features of the RRAM, causing them to exhibit both bipolar resistive switching (BRS) behavior and self-compliance behavior. The current conduction mechanisms of RRAM devices with different film structures were also discussed. Full article
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