Research

9 pages, 38864 KiB

Open AccessArticle

Polymer Coating Effects: Study of Material Properties and Architectural Application Characteristics of Aluminum Template

by Fei Shuo Hung

Coatings 2021, 11(2), 240; https://doi.org/10.3390/coatings11020240 - 17 Feb 2021

Cited by 3 | Viewed by 3146

Abstract

In construction process, the formwork must be in contact with concrete to help the concrete solidify and fix the shape. Coating the formwork with a polymer can prolong its service life by reducing the amount of concrete sticking to the mold. Herein, an [...] Read more.

In construction process, the formwork must be in contact with concrete to help the concrete solidify and fix the shape. Coating the formwork with a polymer can prolong its service life by reducing the amount of concrete sticking to the mold. Herein, an aluminum template substrate was coated with polyvinylidene difluoride (PVDF) or polyurethane (PU). Aluminum template material analysis was conducted, polymer film thickness was measured, and weather, moisture, pollution, salt spray, abrasion, impact, and acid and alkali resistance tests were conducted, as were tensile, bending, adhesion, hardness, and salt water resistance tests. Cement adhesion resistance was repeatedly tested. The experimental results indicated that the PVDF-coated template was superior. The novel PVDF Aluminum template exhibited high corrosion resistance and can be used in building materials, for example, in ceilings, partition walls, curtain walls, roof panels, and roof trusses. For reference, it can also be applied to ship structures and seaside and wind power generation projects. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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9 pages, 2164 KiB

Open AccessArticle

Light Output, Thermal Properties, and Reliability of Using Glass Phosphors in WLED Packages

by Chin-Chuan Huang, Tsung-Han Weng, Chun-Liang Lin and Yan-Kuin Su

Coatings 2021, 11(2), 239; https://doi.org/10.3390/coatings11020239 - 17 Feb 2021

Cited by 7 | Viewed by 2223

Abstract

White-light-emitting diodes (WLED) based on yttrium aluminum garnet (YAG) phosphors sintered with glass (PiG) and with silicone (PiS) are compared in terms of their light properties, temperature properties and reliability.The complete YAG phosphor was doped with an encapsulant traditional WLED (PiS WLED), and [...] Read more.

White-light-emitting diodes (WLED) based on yttrium aluminum garnet (YAG) phosphors sintered with glass (PiG) and with silicone (PiS) are compared in terms of their light properties, temperature properties and reliability.The complete YAG phosphor was doped with an encapsulant traditional WLED (PiS WLED), and the WLED was covered with PiG (PiG WLED). PiG was made by sintering glass powder and YAG phosphor at the ratio of 87:13 (%), and the correlated color temperature (CCT) was 5564 K. The CCT of the PiG WLED with the YAG doping concentration of 8.5 wt.% approximated 5649 K. The initial light output of the PiG WLED was 6.4% lower than that of the PiS WLED. Under 1008 h and 350 mA aging, PiG WLED and PiS WLED’ light output, CCT and color rendering index variation rates were all within 1%. In the saturated vapor-pressure test, no sample exhibited red ink infiltration, light nor peeling between the encapsulant and the lead-frame. Compared with that of the PiS WLED, the junction temperature of the PiG WLED reduced from 88.4 °C to 81.3 °C. Thermal resistance dropped from 37.4 °C/W to 35.6 °C/W. The PiG WLED presented a better CIE (Commission Internationale de l’Eclairage) 1931 chromaticity coordinate (x,y) concentration and thermal properties than the PiS WLED. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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13 pages, 2748 KiB

Open AccessArticle

Characteristics of MgIn₂O₄ Thin Film Transistors Enhanced by Introducing an MgO Buffer Layer

by Wei-De Chen, Sheng-Po Chang and Wei-Lun Huang

Coatings 2020, 10(12), 1261; https://doi.org/10.3390/coatings10121261 - 20 Dec 2020

Viewed by 2105

Abstract

In this work, an MgIn₂O₄ (MIO) thin film transistor (TFT) with a bottom gate structure was fabricated. The MIO channel layer was deposited by RF sputtering using a single MgIn₂O₄ target. The performance of MIO TFT was [...] Read more.

In this work, an MgIn₂O₄ (MIO) thin film transistor (TFT) with a bottom gate structure was fabricated. The MIO channel layer was deposited by RF sputtering using a single MgIn₂O₄ target. The performance of MIO TFT was highly related to oxygen vacancies. As-deposited MIO TFT showed a low field-effect mobility due to doping of Mg. An MgO buffer layer was introduced to enhance the mobility of MIO TFT due to improvement of the interface with the channel layer. In addition, oxygen vacancies in the MIO channel were suppressed because of oxygen diffusion from the buffer layer. MIO TFT with a 5 nm MgO buffer layer showed an on/off current ratio of 9.68 × 10³, a field-effect mobility of 4.81 cm²/V∙s, which was increased more than an order of magnitude compared with the device without a buffer layer, a threshold voltage of 2.01 V, and a subthreshold swing of 0.76 V/decade, which was improved more than 20% compared with the as-deposited one. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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10 pages, 29062 KiB

Open AccessArticle

Electrical Characteristics and Stability Improvement of Top-Gate In-Ga-Zn-O Thin-Film Transistors with Al₂O₃/TEOS Oxide Gate Dielectrics

by Yih-Shing Lee, Yu-Hsin Wang, Tsung-Cheng Tien, Tsung-Eong Hsieh and Chun-Hung Lai

Coatings 2020, 10(12), 1146; https://doi.org/10.3390/coatings10121146 - 24 Nov 2020

Cited by 4 | Viewed by 2700

Abstract

In this work, two stacked gate dielectrics of Al₂O₃/tetraethyl-orthosilicate (TEOS) oxide were deposited by using the equivalent capacitance with 100-nm thick TEOS oxide on the patterned InGaZnO layers to evaluate the electrical characteristics and stability improvement of amorphous indium [...] Read more.

In this work, two stacked gate dielectrics of Al₂O₃/tetraethyl-orthosilicate (TEOS) oxide were deposited by using the equivalent capacitance with 100-nm thick TEOS oxide on the patterned InGaZnO layers to evaluate the electrical characteristics and stability improvement of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) devices, including positive bias stress (PBS) and negative bias stress (NBS) tests. Three different kinds of gate dielectrics (Al₂O₃, TEOS, Al₂O₃/TEOS) were used to fabricate four types of devices, differing by the gate dielectric, as well as its thickness. As the Al₂O₃ thickness of Al₂O₃/TEOS oxide dielectric stacks increased, both the on-current and off-current decreased, and the transfer curves shifted to larger voltages. The lowest ∆V_th of 0.68 V and ∆S.S. of −0.03 V/decade from hysteresis characteristics indicate that the increase of interface traps and charge trapping between the IGZO channel and gate dielectrics is effectively inhibited by using two stacked dielectrics with 10-nm thick Al₂O₃ and 96-nm thick TEOS oxide. The lowest ∆V_th and ∆S.S. values of a-IGZO TFTs with 10-nm thick Al₂O₃ and 96-nm thick TEOS oxide gate dielectrics according to the PBS and NBS tests were shown to have the best electrical stability in comparison to those with the Al₂O₃ or TEOS oxide single-layer dielectrics. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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10 pages, 4392 KiB

Open AccessArticle

New Low-Voltage Driving Compensating Pixel Circuit Based on High-Mobility Amorphous Indium-Zinc-Tin-Oxide Thin-Film Transistors for High-Resolution Portable Active-Matrix OLED Displays

by Ching-Lin Fan, Hou-Yen Tsao, Chun-Yuan Chen, Pei-Chieh Chou and Wei-Yu Lin

Coatings 2020, 10(10), 1004; https://doi.org/10.3390/coatings10101004 - 20 Oct 2020

Cited by 11 | Viewed by 3728

Abstract

In recent years, active-matrix organic light-emitting diodes (AMOLEDs) has been the most popular display for portable application. To satisfy the requirement for the application of the portable display, the design of the compensating pixel circuit with the low-voltage driving and low-power consumption will [...] Read more.

In recent years, active-matrix organic light-emitting diodes (AMOLEDs) has been the most popular display for portable application. To satisfy the requirement for the application of the portable display, the design of the compensating pixel circuit with the low-voltage driving and low-power consumption will be requested. In addition to the circuit with the design of the low-voltage driving, high-mobility thin-film transistors as driving device will be also necessary in order to supply larger driving current at low-voltage driving. Therefore, the study presents a new low-voltage driving AMOLED pixel circuit with high-mobility amorphous indium–zinc–tin–oxide (a-IZTO) thin-film transistors (TFTs) as driving device for portable displays with high resolution. The proposed pixel circuit can simultaneously compensate for the threshold voltage variation of driving TFT (ΔV_{TH_TFT}), OLED degradation (ΔV_{TH_OLED}), and the I-R drop of a power line (ΔV_DD). By using AIM-Spice for simulation based on fabricated a-IZTO TFTs with mobility of 70 cm²V⁻¹S⁻¹ as driving devices, we discovered that the error rates of the driving current were all lower than 5.71% for all input data when ΔV_{TH_TFT} = ±1 V, ΔV_DD = 0.5 V, and ΔV_{TH_OLED} = 0.5 V were all considered simultaneously. We revealed that the proposed 5T2C pixel circuit containing a high-mobility a-IZTO TFT as a driving device was suitable for high-resolution portable displays. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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10 pages, 2671 KiB

Open AccessArticle

Voltage-Tunable UVC–UVB Dual-Band Metal–Semiconductor–Metal Photodetector Based on Ga₂O₃/MgZnO Heterostructure by RF Sputtering

by Jie-Si Jheng, Chun-Kai Wang, Yu-Zung Chiou, Sheng-Po Chang and Shoou-Jinn Chang

Coatings 2020, 10(10), 994; https://doi.org/10.3390/coatings10100994 - 17 Oct 2020

Cited by 7 | Viewed by 2564

Abstract

Dual-band metal–semiconductor–metal (MSM) photodetectors (PDs) with a Ga₂O₃/MgZnO heterostructure were fabricated by radio frequency (RF) sputtering, which can detect ultraviolet C (UVC) and ultraviolet B (UVB) bands individually by controlling different bias voltages. A PD with the annealing temperature [...] Read more.

Dual-band metal–semiconductor–metal (MSM) photodetectors (PDs) with a Ga₂O₃/MgZnO heterostructure were fabricated by radio frequency (RF) sputtering, which can detect ultraviolet C (UVC) and ultraviolet B (UVB) bands individually by controlling different bias voltages. A PD with the annealing temperature of Ga₂O₃ at 600 °C can improve the crystal quality of Ga₂O₃ thin film and exhibit the least persistent photoconductivity (PPC) effect. However, a PD with the annealing temperature of Ga₂O₃ at 600 °C cannot achieve a voltage-tunable dual-band characteristic. On the contrary, the PD without annealing can suppress the carriers from the bottom layer of MgZnO thin film at a lower bias voltage of 1 V. At this time, the peak responsivity at 250 nm was mainly dominated by the top layer of Ga₂O₃ thin film. Then, as the bias voltage increased to 5 V, the peak detection wavelength shifted from 250 (UVC) to 320 nm (UVB). In addition, the PD with a 25 nm–thick SiO₂ layer inserted between Ga₂O₃ and MgZnO thin film can achieve a broader operating bias voltage range for dual-band applications. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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11 pages, 5339 KiB

Open AccessArticle

Au Doping ZnO Nanosheets Sensing Properties of Ethanol Gas Prepared on MEMS Device

by Yempati Nagarjuna and Yu-Jen Hsiao

Coatings 2020, 10(10), 945; https://doi.org/10.3390/coatings10100945 - 30 Sep 2020

Cited by 22 | Viewed by 3201

Abstract

Sensitivity of the Micro Electro Mechanical System (MEMS) device ZnO nanosheets sensor and the Au doped ZnO nanosheets sensor has been investigated. The ZnO samples have been prepared using Hydrothermal synthesis at 90 °C. The prepared ZnO nanostructure is tested for structural morphology [...] Read more.

Sensitivity of the Micro Electro Mechanical System (MEMS) device ZnO nanosheets sensor and the Au doped ZnO nanosheets sensor has been investigated. The ZnO samples have been prepared using Hydrothermal synthesis at 90 °C. The prepared ZnO nanostructure is tested for structural morphology and crystallinity properties. The elemental analysis of the ZnO sample and Au–ZnO samples are tested by using Energy Dispersive X-ray Spectroscopy (EDS) spectrum analysis. MEMS device microheater is designed and prepared for testing the sensitivity of Ethanol gas. Thermal properties of the MEMS microheater is studied for better gas testing at different temperatures. Both the ZnO nanosheets sensor and Au doped ZnO nanosheets sensor are tested using Ethanol gas, and the gas concentrations are taken to be 15, 30, 45, and 60 ppm at 300 °C. The gas sensing response of pure ZnO nanosheets tested for ethanol gas at 60 ppm showed 20%, while the Au–ZnO nanosheets showed 35%, which is increased by 15% at similar operating conditions. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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9 pages, 2657 KiB

Open AccessArticle

Investigation of Conductive Mechanism of Amorphous IGO Resistive Random-Access Memory with Different Top Electrode Metal

by Wei-Lun Huang, Yong-Zhe Lin, Sheng-Po Chang and Shoou-Jinn Chang

Coatings 2020, 10(5), 504; https://doi.org/10.3390/coatings10050504 - 24 May 2020

Cited by 4 | Viewed by 3242

Abstract

In this paper, resistive random-access memory (RRAM) with InGaO (IGO) as an active layer was fabricated by radio-frequency (RF) sputtering system and the resistive switching mechanism with the different top electrode (TE) of Pt, Ti, and Al were investigated. The Pt/IGO/Pt/Ti RRAM exhibits [...] Read more.

In this paper, resistive random-access memory (RRAM) with InGaO (IGO) as an active layer was fabricated by radio-frequency (RF) sputtering system and the resistive switching mechanism with the different top electrode (TE) of Pt, Ti, and Al were investigated. The Pt/IGO/Pt/Ti RRAM exhibits typical bipolar resistive switching features with an average set voltage of 1.73 V, average reset voltage of −0.60 V, average high resistance state (HRS) of 54,954.09 Ω, and the average low resistance state (LRS) of 64.97 Ω, respectively. Ti and Al were substituted for Pt as TE, and the conductive mechanism was different from TE of Pt. When Ti and Al were deposited onto the switching layer, both TE of Ti and Al will form oxidation of TiO_x and AlO_x because of their high activity to oxygen. The oxidation will have different effects on the forming of filaments, which may further affect the RRAM performance. The details of different mechanisms caused by different TE will be discussed. In brief, IGO is an excellent candidate for the RRAM device and with the aids of TiO_x, the set voltage, and reset voltage, HRS and LRS become much more stable. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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9 pages, 2282 KiB

Open AccessArticle

Improved Color Purity of Monolithic Full Color Micro-LEDs Using Distributed Bragg Reflector and Blue Light Absorption Material

by Shao-Yu Chu, Hung-Yu Wang, Ching-Ting Lee, Hsin-Ying Lee, Kai-Ling Laing, Wei-Hung Kuo, Yen-Hsiang Fang and Chien-Chung Lin

Coatings 2020, 10(5), 436; https://doi.org/10.3390/coatings10050436 - 29 Apr 2020

Cited by 19 | Viewed by 3570

Abstract

In this study, CdSe/ZnS core-shell quantum dots (QDs) with various dimensions were used as the color conversion materials. QDs with dimensions of 3 nm and 5 nm were excited by gallium nitride (GaN)-based blue micro-light-emitting diodes (micro-LEDs) with a size of 30 μm [...] Read more.

In this study, CdSe/ZnS core-shell quantum dots (QDs) with various dimensions were used as the color conversion materials. QDs with dimensions of 3 nm and 5 nm were excited by gallium nitride (GaN)-based blue micro-light-emitting diodes (micro-LEDs) with a size of 30 μm × 30 μm to respectively form the green and red lights. The hybrid Bragg reflector (HBR) with high reflectivity at the regions of the blue, green, and red lights was fabricated on the bottom side of the micro-LEDs to reflect the downward light. This could enhance the intensity of the green and red lights for the green and red QDs/micro-LEDs to 11% and 10%. The distributed Bragg reflector (DBR) was fabricated on the QDs color conversion layers to reflect the non-absorbed blue light that was not absorbed by the QDs, which could increase the probability of the QDs excited by the reflected blue light. The blue light absorption material was deposited on the DBR to absorb the blue light that escaped from the DBR, which could enhance the color purity of the resulting green and red QDs/micro-LEDs to 90.9% and 90.3%, respectively. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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8 pages, 3433 KiB

Open AccessArticle

Ambient-Processed, Additive-Assisted CsPbBr₃ Perovskite Light-Emitting Diodes with Colloidal NiO_x Nanoparticles for Efficient Hole Transporting

by Chun-Yuan Huang, Sheng-Po Chang, Arjun G. Ansay, Zi-Hao Wang and Chih-Chiang Yang

Coatings 2020, 10(4), 336; https://doi.org/10.3390/coatings10040336 - 01 Apr 2020

Cited by 10 | Viewed by 3755

Abstract

In this study, the electrically driven perovskite light-emitting diodes (PeLEDs) were investigated by hybridizing the organic polyethylene oxide, 1,3,5-tris (N-phenylbenzimiazole-2-yl) benzene (TPBi), and bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (FIrpic) with CsPbBr₃ in the emission layer and adopting the colloidal NiO_x nanoparticle (NP) hole [...] Read more.

In this study, the electrically driven perovskite light-emitting diodes (PeLEDs) were investigated by hybridizing the organic polyethylene oxide, 1,3,5-tris (N-phenylbenzimiazole-2-yl) benzene (TPBi), and bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (FIrpic) with CsPbBr₃ in the emission layer and adopting the colloidal NiO_x nanoparticle (NP) hole transport layer. The synthesized NiO_x NPs, having an average size of ~5 nm, can be spin-coated to become a smooth and close-packed film on the indium–tin–oxide anode. The NiO_x NP layer possesses an overall transmittance of ~80% at 520 nm, which is about the peak position of electroluminescence (EL) spectra of CsPbBr₃ emission layer. The coating procedures of NiO_x NP and CsPbBr₃ layers were carried out in ambient air. The novel PeLED turned on at 2.4 V and emitted bright EL of 4456 cd/m² at 7 V, indicating the remarkable nonradiative-related defect elimination by organic additive addition and significant charge balance achieved by the NiO_x NP layer. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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8 pages, 5760 KiB

Open AccessArticle

Material Application of a Transformer Box: A Study on the Electromagnetic Shielding Characteristics of Al–Ta Coating Film with Plasma-Spray Process

by Fei-Shuo Hung

Coatings 2019, 9(8), 495; https://doi.org/10.3390/coatings9080495 - 06 Aug 2019

Cited by 8 | Viewed by 3077

Abstract

In this study we present the results of two experiments. In the first one, a Ta–Al–SS (stainless steel (SS)) multilayer coating structure was prepared using plasma spraying equipment to investigate the coating structure and interface properties. In the second one, Ta–Al on multilayer [...] Read more.

In this study we present the results of two experiments. In the first one, a Ta–Al–SS (stainless steel (SS)) multilayer coating structure was prepared using plasma spraying equipment to investigate the coating structure and interface properties. In the second one, Ta–Al on multilayer glass was prepared using the sputtering process to measure the thickness effect of thin film on electromagnetic wave shielding (EMI) characteristics and on the design of high-power switchboard covers. According to the experimental results, the multilayer structure of Ta–Al on SS improves the mechanical properties of a stainless steel plate by enhancing the explosion-proof property. An appropriate thickness of the plasma-sprayed pure aluminum layer can increase the adhesion to the stainless steel substrate and buffer the stress effect. After heat treatment (annealing), the Ta–Al–SS multilayer structural characteristics are excellent and suitable for shielding effects at different temperatures and humidity, which can be used as a reference for the engineering application of communication rooms and base power stations. According to EMI test of multi-coated glass (Ta–Al–glass), by increasing the thickness of Ta layer, we cannot effectively improve full-frequency EMI shielding with improved shielding at low-mid frequency condition. In addition, the Ta–Al interface formation of an Al–Ta–O compound layer can improve the adiabatic effect to reduce the thermal conductivity. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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7 pages, 2681 KiB

Open AccessArticle

TiO₂ Nano Flowers Based EGFET Sensor for pH Sensing

by Chih-Chiang Yang, Kuan-Yu Chen and Yan-Kuin Su

Coatings 2019, 9(4), 251; https://doi.org/10.3390/coatings9040251 - 15 Apr 2019

Cited by 31 | Viewed by 5337

Abstract

In this study, pH sensors were successfully fabricated on a fluorine-doped tin oxide substrate and grown via hydrothermal methods for 8 h for pH sensing characteristics. The morphology was obtained by high-resolution scanning electron microscopy and showed randomly oriented flower-like nanostructures. The TiO [...] Read more.

In this study, pH sensors were successfully fabricated on a fluorine-doped tin oxide substrate and grown via hydrothermal methods for 8 h for pH sensing characteristics. The morphology was obtained by high-resolution scanning electron microscopy and showed randomly oriented flower-like nanostructures. The TiO₂ nanoflower pH sensors were measured over a pH range of 2–12. Results showed a high sensitivity of the TiO₂ nano-flowers pH sensor, 2.7 (μA)^1/2/pH, and a linear relationship between I_DS and pH (regression of 0.9991). The relationship between voltage reference and pH displayed a sensitivity of a 46 mV/pH and a linear regression of 0.9989. The experimental result indicated that a flower-like TiO₂ nanostructure extended gate field effect transistor (EGFET) pH sensor effectively detected the pH value. Full article

(This article belongs to the Special Issue Advances in Thin Film Transistors: Properties and Applications)

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