Browsing by Author "Wang, Wei-Lin"

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Crystal Quality of 3C-SiC Influenced by the Diffusion Step in the Modified Four-Step Method
(2010)
Chen, Wei-Yu
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Wang, Wei-Lin
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Liu, Jui-Min
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Chen, Chien-Cheng
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Hwang, Jenn-Chang
The atomic arrangement and bonding characteristics of void-free 3C-SiC/Si(100) grown by the modified four-step method are presented. Without the diffusion step, Si-C bonds are partially formed in the as-carburized layer on Si(100). The ratio of C-C bonds to Si-C bonds is about 7:3, which can be lowered to about 1:9 after the diffusion step at 1350 degrees C for 5 min or at 1300 degrees C for 7 min according to C 1s core level spectra. The residual C-C bonds cannot be removed, which is associated with an irregular atomic arrangement (amorphous) located either at the 3C-SiC/Si(100) interface or at the intersection of twin boundaries in the 3C-SiC buffer layer based on the lattice image taken by transmission electron microscope. The diffusion step helps the formation of Si-C bonds more completely and results in a SiC buffer layer of high quality formed on Si(100) before the growth step. However, twins and stacking faults still appear in the 3C-SiC buffer layer after the diffusion step. The formation mechanism of the 3C-SiC buffer layer is proposed and discussed.
Defects in m-plane ZnO epitaxial films grown on (112) LaAlO(3) substrate
(2011-05-01)
Wang, Wei-Lin
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Peng, Chun-Yen
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Ho, Yen-Teng
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Chuang, Shu-Chang
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Chang, Li
The crystallographic orientations of m-plane ZnO on (112) LaAlO(3) (LAO) substrate are [(1) over bar2 (1) over bar0](ZnO)parallel to[11 (1) over bar](LAO) and [0001](ZnO)parallel to[(1) over bar 10](LAO). The defects in m-plane ZnO have been systematically investigated using cross section and plan-view transmission electron microscopy (TEM). High-resolution TEM observations in cross section show misfit dislocations and basal stacking faults (BSFs) at the ZnO/LAO interface. In the films, threading dislocations (TDs) with 1/3 < 11 (2) over bar0 > Burgers vectors are distributed on the basal plane, and BSFs have 1/6 < 20 (2) over bar3 > displacement vector. The densities of dislocations and BSFs are estimated to be 5.1 x 10(10) cm(-2) and 4.3 x 10(5) cm(-1), respectively. In addition to TDs and BSFs, plan-view TEM examination also reveals that stacking mismatch boundaries mainly lie along the m-planes and they connect with planar defect segments along the r-planes. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3539046]
Defects in m-plane ZnO epitaxial films grown on (112) LaAlO3 substrate
(2011-05-01)
Wang, Wei-Lin
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Peng, Chun-Yen
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Ho, Yen-Teng
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Chuang, Shu-Chang
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Chang, Li
The crystallographic orientations of m-plane ZnO on (112) LaAlO3 (LAO) substrate are [(1) over bar2 (1) over bar0](ZnO)parallel to[11 (1) over bar](LAO) and [0001](ZnO)parallel to[(1) over bar 10](LAO). The defects in m-plane ZnO have been systematically investigated using cross section and plan-view transmission electron microscopy (TEM). High-resolution TEM observations in cross section show misfit dislocations and basal stacking faults (BSFs) at the ZnO/LAO interface. In the films, threading dislocations (TDs) with 1/3 < 11 (2) over bar0 > Burgers vectors are distributed on the basal plane, and BSFs have 1/6 < 20 (2) over bar3 > displacement vector. The densities of dislocations and BSFs are estimated to be 5.1 x 10(10) cm(-2) and 4.3 x 10(5) cm(-1), respectively. In addition to TDs and BSFs, plan-view TEM examination also reveals that stacking mismatch boundaries mainly lie along the m-planes and they connect with planar defect segments along the r-planes. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3539046]
Defects in nonpolar (13(4)over-bar0) ZnO epitaxial film grown on (114) LaAlO3 substrate
(2014-03-01)
Yen, Tzu-Chun
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Wang, Wei-Lin
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Peng, Chun-Yen
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Tian, Jr-Sheng
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Ho, Yen-Teng
The defects in (13 (4) over bar0)ZnO epitaxial film grown on (114)LaAlO3 (LAO) have been systematically investigated by using transmission electron microscopy. At the ZnO/LAO interface, the Burgers vectors of misfit dislocations are identified to be 1/3[(1) over bar2 (1) over bar0] and 1/2[0001]. Threading dislocations with the Burgers vectors of 1/3 < 11 (2) over bar0 > and < 0001 > are distributed on the basal plane. In (13 (4) over bar0)ZnO film, the predominant planar defects are basal stacking faults (BSFs) with 1/6 < 20 (2) over bar3 > displacement vectors. The densities of dislocations and BSFs are about 3.8 x 10(10) cm(-2) and 3.1 x 10(5) cm(-1), respectively. (C) 2014 American Vacuum Society.
Diamond plates on dome-like particles: preparation, characterization and field emission properties
(2010-08-01)
Tiwari, Rajanish N.
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Chen, Wei-Chun
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Tiwari, Jitendra N.
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Wang, Wei-Lin
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Chang, Li
Thin diamond microplates have been grown on dome-like/hemispherical carbon particles on titanium carbide by a microwave plasma chemical vapour deposition (MPCVD) method using a gas mixture of methane and hydrogen. The diamond microplates have a thickness of about 200 nm. A thin (300 nm) film of titanium carbide was formed during carburization of sputtered titanium on an Si(100) substrate in MPCVD. The hemispherical carbon particles were covered with diamond microplates. The diamond microplates are isolated electron-emitting spherules and exhibit a low threshold (50 V mu m (1)) and high current density (0.92 mA cm(-2)) in their field emission properties. A possible mechanism for the formation of the diamond microplates and hemispherical carbon particles is presented.
Effect of growth temperature on a-plane ZnO formation on r-plane sapphire
(2011-05-01)
Peng, Chun-Yen
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Tian, Jr-Sheng
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Wang, Wei-Lin
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Ho, Yen-Teng
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Chuang, Shu-Chang
The effect of growth temperature on a-plane ZnO formation on r-plane sapphire has been systematically investigated by employing in situ high pressure reflection high-energy electron diffraction, atomic force microscopy, and high-resolution x-ray diffraction. For film growth above and below 600 degrees C, it is shown that there is a significant difference in growth rate and surface morphology due to the differences in the growth mode. Stripelike morphologies were observed on the surface of a-plane ZnO grown at low temperature (LT) because of differences in the growth rate along the c-axis and the growth rate normal to the c-axis. Furthermore, annealing of films grown at low temperature results in more pronounced stripe morphology and in improvement of crystallinity. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3549141]
Epitaxial growth of semipolar InN(10(1)over-tilde3) on LaAlO3 substrate: Epitaxial relationship analysis
(2017-05-01)
Chen, Wei-Chun
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Kuo, Shou-Yi
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Tian, Jr. -Sheng
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Wang, Wei-Lin
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Lai, Fang-I
Epitaxial semipolar InN(10 (1) over tilde3) crystals were grown on a LaAlO3(112) substrate using radio frequency plasma-assisted molecular beam epitaxy without any interlayer. The lattice mismatch between InN and LaAlO3 was estimated to be % 7.75% along the [1 (2) over tilde 10](InN) direction and 0.2% along the [(3) over tilde 032](InN) direction. The InN film is epitaxic with the LaAlO3 substrate, with orientation relationships between InN(10 (1) over tilde3) parallel to LaAlO3(112) and [1 (2) over tilde 10](InN) parallel to [11 (1) over tilde](LAO). InN grown on LaAlO3(112) appears (10 (1) over tilde3) plane orientated, with two types of domains. Semipolar InN(10 (1) over tilde3) layers can be grown at 510 degrees C and show X-ray rocking curve FWHMs of 1830 and 1408 arcsec for InN(0002) and InN(10 (1) over tilde3), respectively. However, InN grown at 510 degrees C has the highest peak intensity and the narrowest FWHM of the prepared samples, indicating high-quality crystal growth. (C) 2017 The Japan Society of Applied Physics
Epitaxy of m-plane ZnO on (112) LaAlO(3) substrate
(2009-05-01)
Ho, Yen-Teng
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Wang, Wei-Lin
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Peng, Chun-Yen
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Chen, Wei-Chun
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Liang, Mei-Hui
Heteroepitaxial growth of non-polar in-plane (10 (1) over bar0) ZnO has been demonstrated on (112) LaAlO(3) single crystal substrates using the pulsed laser deposition method. X-ray diffraction, reflection high energy electron diffraction, and cross-sectional transmission electron microscopy with selected-area diffraction, have been used to characterize the structural properties of deposited ZnO films. The epitaxial relationship between ZnO and LAO is shown to be (10 (1) over bar0)(ZnO) parallel to (112)(LAO), (11 (2) over bar0)(ZnO) parallel to ((1) over bar(1) over bar1)(LAO), and [0001](ZnO) parallel to [(1) over bar 10](LAO). (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Epitaxy of m-plane ZnO on (112) LaAlO3 substrate
(2009-05-01)
Ho, Yen-Teng
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Wang, Wei-Lin
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Peng, Chun-Yen
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Chen, Wei-Chun
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Liang, Mei-Hui
Heteroepitaxial growth of non-polar in-plane (10 (1) over bar0) ZnO has been demonstrated on (112) LaAlO3 single crystal substrates using the pulsed laser deposition method. X-ray diffraction, reflection high energy electron diffraction, and cross-sectional transmission electron microscopy with selected-area diffraction, have been used to characterize the structural properties of deposited ZnO films. The epitaxial relationship between ZnO and LAO is shown to be (10 (1) over bar0)(ZnO) parallel to (112)(LAO), (11 (2) over bar0)(ZnO) parallel to ((1) over bar(1) over bar1)(LAO), and [0001](ZnO) parallel to [(1) over bar 10](LAO). (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Fabrication and structural property of diamond nano-platelet arrays on {111) textured diamond film
(2012-05-01)
Wang, Wei-Lin
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Wang, Sheng-Ming
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Cho, Shih-Yin
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Chang, Li
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材料科學與工程學系
Diamond nano-platelet (DNP) arrays have been grown on {111} textured diamond film by using micro-wave plasma enhanced chemical vapor deposition system. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been used to characterize the growth behavior and micro-structure of DNP arrays on diamond film. According to the results of SEM and TEM images, DNP arrays only appear on the {111} surfaces of underlying diamond grains. Both DNPs and underlying diamond grains comprise penetration {111} twin structures. The growth of DNPs is the extension of the penetration {111} twins from underlying diamond grains. The accommodation and glide of stacking faults can also evolve into perfect {111} twin structures during the growth of DNPs. (C) 2012 Elsevier B.V. All rights reserved.
Growth and characterization of diamond films on TiN/Si(100) by microwave plasma chemical vapor deposition
(2009-02-01)
Chen, Wei-Chun
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Wang, Wei-Lin
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Tiwari, Rajanish N.
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Chang, Li
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材料科學與工程學系
Polycrystalline diamond films were deposited on silicon (100) substrate by microwave plasma chemical vapor disposition (MPCVD) using similar to 300 nm thick < 001 > textured titanium nitride (TiN) films as buffer layer which were prepared by radio-frequency reactive sputtering. The diamond/TiN films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. The results show that no apparent change can be observed for the < 100 > oriented TiN buffer layers after MPCVD even with a negative bias voltage applied onto the substrates. (C) 2008 Published by Elsevier B.V.
Growth of 3C-SiC on Si(111) using the four-step non-cooling process
(2010-08-02)
Liu, Jui-Min
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Chen, Wei-Yu
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Hwang, J.
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Huang, C-F.
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Wang, Wei-Lin
A modified four-step method was applied to grow a 3C-SiC thin film of high quality on the off-axis 1.5 degrees Si(111) substrate in a mixed gas of C(3)H(8), SiH(4) and H(2) using low pressure chemical vapor deposition. The modified four-step method adds a diffusion step after the carburization step and removes the cooling from the traditional threestep method (clean, carburization, and growth). The X-ray intensity of the 3C-SiC(111) peak is enhanced from 5 x 10(4) counts/s (the modified three steps) to 1.1 x 10(5) counts/s (the modified four steps). The better crystal quality of 3C-SiC is confirmed by the X-ray rocking curves of 3C-SiC(111). 3C-SiC is epitaxially grown on Si( 111) supported by the selected area electron diffraction patterns taken at the 3C-SiC/Si(111) interface. Some (111) stacking faults and twins appear inside the 3C-SiC, which may result from the stress induced in the 3C-SiC thin film due to lattice mismatch. The diffusion step plays roles in enhancing the formation of Si-C bonds and in reducing the void density at the 3C-SiC/Si(111) interface. (C) 2010 Elsevier B.V. All rights reserved.
Growth of nonpolar (11(2)over-bar0) ZnO films on LaAlO(3) (001) substrates
(2008-09-22)
Ho, Yen-Teng
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Wang, Wei-Lin
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Peng, Chun-Yen
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Liang, Mei-Hui
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Tian, Jr-Sheng
Nonpolar (11 (2) over bar0) ZnO films were grown on LaAlO(3) (001) single crystal substrates at temperature from 300 to 750 S C by pulsed laser deposition method. The films were examined using x-ray diffraction, reflection high energy electron diffraction, and photoluminescence measurements for the crystallinity. The surface morphology of ZnO films from atomic force microscopy exhibits L-shaped domains. Cross-sectional transmission electron microscopy with selected area diffraction reveals two types of a-plane ZnO domains perpendicular to each other with in-plane orientation relationships of [0001](ZnO)
Growth of Semipolar InN(10(1)over-bar3) on LaAlO(3)(112) Substrate
(2011-04-01)
Chen, Wei-Chun
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Tian, Jr-Sheng
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Wang, Wei-Lin
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Ho, Yen-Teng
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Chang, Li
In this study, we report the growth and characterization of semipolar (10 (1) over bar3) InN films grown on LaAlO(3)(112) substrate by metalorganic molecular beam epitaxy. InN films were grown at various substrate temperatures in the range of 465-540 degrees C. Structural and optical properties of semipolar InN were investigated by high resolution X-ray diffraction, scanning electron microscopy, and photoluminescence measurements. The results show that semipolar (10 (1) over bar3) InN layers can be grown at 510 degrees C with the full-width at half maximum of the X-ray rocking curve about 1400 arcsec and electron mobility of 494 cm(2)V(-1)s(-1). (C) 2011 The Japan Society of Applied Physics
Growth of Semipolar InN(10(1)over-bar3) on LaAlO3(112) Substrate
(2011-04-01)
Chen, Wei-Chun
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Tian, Jr-Sheng
;
Wang, Wei-Lin
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Ho, Yen-Teng
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Chang, Li
In this study, we report the growth and characterization of semipolar (10 (1) over bar3) InN films grown on LaAlO3(112) substrate by metalorganic molecular beam epitaxy. InN films were grown at various substrate temperatures in the range of 465-540 degrees C. Structural and optical properties of semipolar InN were investigated by high resolution X-ray diffraction, scanning electron microscopy, and photoluminescence measurements. The results show that semipolar (10 (1) over bar3) InN layers can be grown at 510 degrees C with the full-width at half maximum of the X-ray rocking curve about 1400 arcsec and electron mobility of 494 cm(2)V(-1)s(-1). (C) 2011 The Japan Society of Applied Physics
Growth of ZnMgO/ZnO films on r-plane sapphires by pulsed laser deposition
(2008-04-01)
Liang, Mei-Hui
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Ho, Yen-Teng
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Wang, Wei-Lin
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Peng, Chun-Yen
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Chang, Li
High-quality ZnMgO/ZnO multi-layer thin films in a-plane orientation were grown by pulsed laser deposition on r-plane sapphires. Reflection high-energy electron diffraction (RHEED) patterns were performed to monitor the growth morphology and the epitaxy. X-ray diffraction, RHEED, and atomic force microscopy show that anisotropic growth of a-plane ZnO results in stripe morphology, and the difference of thermal expansion between ZnO and sapphire plays a significant role on the film surface smoothness. Cross-sectional transmission electron microscopy identifies the cause of disorientation of ZnO growth on sapphire. (C) 2007 Elsevier B.V. All rights reserved.
Heteroepitaxial growth of InN on GaN intermediate layer by PA-MOMBE
(2011-07-01)
Lai, Fang-I
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Kuo, Shou-Yi
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Chen, Wei-Chun
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Lin, Woei-Tyng
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Wang, Wei-Lin
In this paper, high-quality wurtzite indium nitride was epi-grown on sapphire substrates by plasma-assisted metal-organic molecule beam epitaxy system (PA-MOMBE). Structural and electrical properties of the InN films were significantly improved by employing a GaN buffer layer. In addition, high-resolution X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy (TEM), Hall Effect, Raman and photoluminescence spectroscopy were carried out to characterize the effect of the growth temperature on structural and optoelectronic properties. It was found that highly c-axis oriented InN epilayer can be obtained by optimizing growth conditions. TEM images reveal that the epitaxially grown InN/GaN interface is sharp, and the spacing of the InN(0 0 0 2) lattice plane is about 0.57 nm. Raman spectra also show a sharp peak at 491 cm(-1) attributed to the E(2)(high) mode of wurtzite InN. These results indicate that the improvement of InN material quality can be achieved using heteroepitaxy on GaN/sapphire templates. (C) 2011 Elsevier B.V. All rights reserved.
Influence of V/III Flow Ratio on Growth of InN on GaN by PA-MOMBE
(2013)
Chen, Wei-Chun
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Tian, Jr-Sheng
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Wu, Yue-Han
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Wang, Wei-Lin
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Kuo, Shou-Yi
InN epilayers were prepared on c-GaN/sapphire substrates by plasma-assisted metal-organic molecular beam epitaxy using N-2 and trimethylindium precursor as the V/III sources. We studied the influence of the V/III flow ratio on the film structure, surface morphology, film compositions, and optical and electrical properties using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction, X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), photoluminescence (PL) measurement and Hall effect. The results show that epitaxial InN films can be obtained with the V/III ratio in the range between 1.81 and 4 at 500 degrees C. The InN growth rate decreases from 1.9 to 1.4 mu m/h when the ratio increases from 1.81 to 4. The surfaces of the InN films are not smooth in the V/III range used. Cross-sectional TEM revealed that the planar defect density in InN is as high as similar to 1.5 x 10(6) cm(-1) at a V/III ratio of similar to 1.81. XPS and SIMS results show that the film surface contains oxygen, which is found to affect the measured carrier mobility and concentration. (C) 2013 The Electrochemical Society. All rights reserved.
Interfacial structure of a-plane ZnO grown on r-plane sapphire by pulsed laser deposition
(2013-03-01)
Peng, Chun-Yen
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Wang, Wei-Lin
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Ho, Yen-Teng
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Tian, Jr-Sheng
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Chang, Li
In this study, interfacial structure of a-ZnO with misfit accommodation on r-sapphire at low and high growth temperatures (LT and HT) by pulsed laser deposition is presented. Along [1 (1) over bar 00](ZnO) of large lattice mismatch of ZnO with sapphire, TEM examinations show that a-type misfit dislocations are spaced 1.3-2.2 nm on HT-ZnO/sapphire interface, whereas dislocation pairs in spacing of 2.8-3.5 nm are observed for LT-ZnO/sapphire. For smaller lattice mismatch along the ZnO c-axis direction, reciprocal space maps of (11 (2) over bar(2) over bar)(ZnO) and (30 (3) over bar0)(sapphire) reflections show that HT-ZnO is nearly fully strained without much relaxation and has a highly coherent interface with sapphire, in contrast with partial relaxation in LT-ZnO. (C) 2012 Elsevier B.V. All rights reserved.
Investigating Size Personalization for More Accurate Eye Tracking Glasses
(2017-01-01)
Hsieh, Yi-Yu
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Liu, Chia-Chen
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Wang, Wei-Lin
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Chuang, Jen-Hui
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交大名義發表
Personalized eyewear frame could improve the accuracy of eye tracking. To obtain the personalized frame size (temple length), we propose a new measuring instrument that consists of (i) the hardware, a 3D printed trial frame which has marks but no scales, and (ii) the software, a vision-based measurement which is view invariant. The vision-based measurement has accuracy and precision that are both 0.02 cm, while the trial frame can achieve a precision of 0.17 cm for secure wearing. Moreover, dispersion up to 2.56 cm is obtained among the personalized frame sizes for just a fairly small group of users, indicating the importance of having such a personalized measurement system.