Browsing by Author "Peng, Chun-Yen"

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Comparison of single-/few-/multi-mode 850 nm VCSELs for optical OFDM transmission
(2017-07-10)
Kao, Hsuan-Yun
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Tsai, Cheng-Ting
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Leong, Shan-Fong
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Peng, Chun-Yen
;
Chi, Yu-Chieh
For high-speed optical OFDM transmission applications, a comprehensive comparison of the homemade multi-/few-/single-transverse mode (MM/FM/SM) vertical cavity surface emitting laser (VCSEL) chips is performed. With microwave probe, the direct encoding of pre-leveled 16-QAM OFDM data and transmission over 100-m-long OM4 multi-mode-fiber (MMF) are demonstrated for intra-datacenter applications. The MM VCSEL chip with the largest emission aperture of 11 mu m reveals the highest differential quantum efficiency which provides the highest optical power of 8.67 mW but exhibits the lowest encodable bandwidth of 21 GHz. In contrast, the SM VCSEL chip fabricated with the smallest emission aperture of only 3 mu m provides the highest 3-dB encoding bandwidth up to 23 GHz at a cost of slight heat accumulation. After optimization, with the trade-off set between the receiving signal-to-noise ratio (SNR) and bandwidth, the FM VCSEL chip guarantees the highest optical OFDM transmission bit rate of 96 Gbit/s under back-to-back case with its strongest throughput. Among three VCSEL chips, the SM VCSEL chip with nearly modal-dispersion free feature is treated as the best candidate for carrying the pre-leveled 16-QAM OFDM data over 100-m OM4-MMF with same material structure but exhibits different oxide-layer confined gain cross-sections with one another at 80-Gbit/s with the smallest receiving power penalty of 1.77 dB. (C) 2017 Optical Society of America
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
;
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
;
Peng, Chun-Yen
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Ho, Yen-Teng
;
Chuang, Shu-Chang
;
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
;
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.
Defects in semipolar (11(2)over-bar(2)over-bar) ZnO grown on (112) LaAlO3/(La, Sr) (Al, Ta)O-3 substrate by pulsed laser deposition
(2013-03-27)
Tian, Jr-Sheng
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Wu, Yue-Han
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Peng, Chun-Yen
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Chiu, Kun-An
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Shih, Yi-Sen
The microstructure of semipolar (11 (2) over bar(2) over bar) ZnO deposited on (112) LaAlO3/(La, Sr) (Al, Ta)O-3 was investigated by transmission electron microscopy. The ZnO shows an in-plane epitaxial relationship of [11 (2) over bar3](ZnO) parallel to [11 (1) over bar](LAO/LSAT) with oxygen-face sense polarity. The misfit strain along [11 (2) over bar3](ZnO) and [1 (1) over bar 00](ZnO) is relieved through the formation of misfit dislocations with the Burgers vectors b = 1/6[11 (2) over bar3](ZnO) and b = 1/3 < 1 (2) over bar 10 >(ZnO), respectively. The line defects in the semipolar ZnO are predominantly perfect dislocations, and the dislocation density decreases with increasing ZnO thickness as a result of dislocation reactions. Planar defects were observed to lie in the M-plane and extend along < 0001 >, whereas basal stacking faults were rarely found.
Design and Optimization of VCSELs for up to 40-Gb/s Error-Free Transmission Through Impurity-Induced Disordering
(2020-03-01)
Peng, Chun-Yen
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Cheng, Hao-Tien
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Kuo, Hao-Chung
;
Wu, Chao-Hsin
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光電工程學系
This article describes an optimized design and process for the improvement of the electrical properties of vertical-cavity surface-emitting lasers (VCSELs) via the impurity-induced disordering (IID) technology. Through the IID process, the electrical current path can be tailored to detour around the defect centers introduced by the oxidation process, resulting in a noticeable improvement in the dc and the RF characteristics of the IID VCSEL. The threshold current was reduced from 0.341 to 0.225 mA due to better current injection efficiency in the IID VCSEL. The characteristic temperature of the IID VCSEL increased from 106 to 150 K, and the slope of the I-V characteristics under low-level-injection regime could be improved to a factor of exp. The RF characteristics also echoed the dc characteristics, which the optical bandwidth of the IID VCSEL enhanced from 18.95 to 23.49 GHz, and showed a prominent difference on the factor (similar to 0.26 to similar to 0.22 ns) and the D factor (similar to 7 to similar to 11 GHz/(mA)(1/2)). The IID VCSEL is then employed for a data transmission link, an eye diagram was characterized at up to 44 Gb/s and passed 40-Gb/s error-free testing under on-off-keying (OOK) modulation.
Developing and evaluating an IT specification extraction system
(2006)
Yang, Chyan
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Chen, Liang-Chu
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Peng, Chun-Yen
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經營管理研究所
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資訊管理與財務金融系註：原資管所+財金所
Purpose - This paper seeks to establish an extraction system for an information technology (IT) product specification named ITSIES which combines the natural language process (NLP) with the ontology concept and also to evaluate the system's effectiveness in advance. Design/methodology/approach - The development of the system is based on a prototype design and performance validation. This study adopts four classes of IT specification (PC, Unix server, Monitor, and Printer) that follow IBM's and HP's product lines as the baseline information in order to construct the extraction system in GATE (General Architecture for Text Engineering) tools and to examine the IT product specification with other brands and patterns. Additionally indices are adopted such as precision, recall, and F-measure as the matrices for evaluating system performance. Findings - The performance shows that the average recall, precision, and F-measure are all over 90 per cent, revealing that the JAPE (Java Annotation Patterns Engine) grammar rules in the IT domain are reasonably good and generally in line with expectations. Originality/value - The paper proposes an integrative framework to examine IT product specification information and demonstrates that the system is effective for IT application.
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]
Effect of In/Al ratios on structural and optical properties of InAlN films grown on Si(100) by RF-MOMBE
(2014-05-01)
Chen, Wei-Chun
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Wu, Yue-Han
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Peng, Chun-Yen
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Hsiao, Chien-Nan
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Chang, Li
InxAl1-xN films were deposited on Si(100) substrate using metal-organic molecular beam epitaxy. We investigated the effect of the trimethylindium/trimethylaluminum (TMIn/TMAI) flow ratios on the structural, morphological, and optical properties of InxAl1-xN films. Surface morphologies and microstructure of the InxAl1-xN films were measured by atomic force microscopy, scanning electron microscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM), respectively. Optical properties of all films were evaluated using an ultraviolet/visible/infrared (UV/Vis/IR) reflection spectrophotometer. XRD and TEM results indicated that InxAl1-xN films were preferentially oriented in the c-axis direction. Besides, the growth rates of InxAl1-xN films were measured at around 0.6 mu m/h in average. Reflection spectrum shows that the optical absorption of the InxAl1-xN films redshifts with an increase in the In composition.
Epitaxial integration of a nanoscale BiFeO3 phase boundary with silicon
(2016-01-01)
Liang, Wen-I
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Peng, Chun-Yen
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Huang, Rong
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Kuo, Wei-Cheng
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Huang, Yen-Chin
The successful integration of the strain-driven nanoscale phase boundary of BiFeO3 onto a silicon substrate is demonstrated with extraordinary ferroelectricity and ferromagnetism. The detailed strain history is delineated through a reciprocal space mapping technique. We have found that a distorted monoclinic phase forms prior to a tetragonal-like phase, a phenomenon which may correlates with the thermal strain induced during the growth process.
Epitaxial integration of a nanoscale BiFeO3 phase boundary with silicon
(2016)
Liang, Wen-I
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Peng, Chun-Yen
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Huang, Rong
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Kuo, Wei-Cheng
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Huang, Yen-Chin
The successful integration of the strain-driven nanoscale phase boundary of BiFeO3 onto a silicon substrate is demonstrated with extraordinary ferroelectricity and ferromagnetism. The detailed strain history is delineated through a reciprocal space mapping technique. We have found that a distorted monoclinic phase forms prior to a tetragonal-like phase, a phenomenon which may correlates with the thermal strain induced during the growth process.
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
;
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
Few-mode VCSEL chip for 100-Gb/s transmission over 100 m multimode fiber
(2017-10-01)
Kao, Hsuan-Yun
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Chi, Yu-Chieh
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Tsai, Cheng-Ting
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Leong, Shan-Fong
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Peng, Chun-Yen
A few-mode (FM) vertical cavity surface emitting laser (VCSEL) chip with heavily zinc-diffused contact layer and oxide-confined cross-section is demonstrated for carrying pre-leveled 16-quadrature amplitude modulation orthogonal frequency division multiplexing (QAM-OFDM) data in OM4 multi-mode fiber (MMF) over 100 m for intra-data-center applications. The FM VCSEL chip, which has an oxide-confined emission aperture of 5 mu m, demonstrates high external quantum efficiency, provides an optical power of 2.2 mW at 38 times threshold condition, and exhibits 3 dB direct-modulation bandwidth beyond 22 GHz at a cost of slight heat accumulation. At a DC bias point of 5 mA (22.6I(th)) the FM VCSEL chip, with sufficiently normalized modulation output, supports Baud and data rates of 25 and 100 Gb/s, respectively, with forward error correction (FEC) certifying receiving quality after back-to-back transmission. After passing through 100 m OM4 MMF with a receiving power penalty of 4 dB, the FM VCSEL chip demonstrates FEC-certified transmission of the pre-leveled 16-QAM OFDM data at 92 Gb/s. (C) 2017 Chinese Laser Press
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 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 TiN film on MgO (100) by reactive magnetron sputtering
(2014-10-03)
Chen, Wei-Chun
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Peng, Chun-Yen
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Chang, Li
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材料科學與工程學系
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Department of Materials Science and Engineering
TiN thin films were deposited on MgO (100) substrates at different substrate temperatures using rf sputtering with Ar/N-2 ratio of about 10. At 700 degrees C, the growth rate of TiN was approximately 0.05 mu m/h. The structural and electrical properties of TiN thin films were characterized with x-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Hall measurements. For all deposition conditions, XRD results show that the TiN films can be in an epitaxy with MgO with cube-on-cube orientation relationship of (001)(TiN) // (001)(MgO) and [100](TiN) // [100](MgO). TEM with selected-area electron diffraction pattern verifies the epitaxial growth of the TiN films on MgO. SEM and AFM show that the surface of the TiN film is very smooth with roughness approximately 0.26 nm. The minimum resistivity of the films can be as low as 45 mu Omega cm.
High-Temperature Insensitivity of 50-Gb/s 16-QAM-DMT Transmission by Using the Temperature-Compensated Vertical-Cavity Surface-Emitting Lasers
(2018-08-15)
Peng, Chun-Yen
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Tsai, Cheng-Ting
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Wang, Huai-Yung
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Wu, Yun-Chen
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Shih, Tien-Tsorng
In this study, a 50-Gb/s 16-quadrature amplitude modulation discrete multitone (16-QAM-DMT) was applied to an 850-nm oxide-confined vertical-cavity surface-emitting laser (VCSEL) at various temperature ranging from 25 degrees C to 85 degrees C. This study reports the highest bit rate for directly modulated VCSELs operating at 85 degrees C, in addition to demonstrating, for the first time, 16-QAM-DMT with less dependence on slope efficiency (SE) reduction. By using a temperature-compensated VCSEL, this study determined the degradation of the bit error rate (BER) in terms of the signal-to-noise ratio. The analysis results demonstrate that the transmission quality is dominated by optical bandwidth rather than the SE. Therefore, the preleveling technique was applied for error rate recovery to reduce the BER from 6.3 x 10(-3) to 3.8 X 10(-3) with a 0.2-dB/GHz preleveling slope. Thus, a low-bandwidth system (nearly 10 GHz) was realized for high data-rate transmissions (50 Gb/s) at 85 degrees C. The 16-QAM-DMT transmission provides an effective approach to alleviating thermal problems that occur in high-speed optical communication without the requirement of any external amplification circuits.
Homoepitaxial growth and stress analysis of (111) diamond film with embedded gold islands
(2015-08-01)
Chiu, Kim-An
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Wu, Ping-Hsun
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Peng, Chun-Yen
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Tian, Jr-Sheng
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Chang, Li
The internal stress in high-quality (111) homoepitaxial diamond film grown on high-pressure high temperature (HPHT) synthesized single crystal diamond substrate by chemical vapor deposition (CVD) can be reduced effectively by embedding Au islands in diamond. Au islands formed from an Au layer deposited on the diamond substrate by electron beam evaporation can be obtained after hydrogen plasma annealing. Transmission electron microscopy and X-ray diffraction results show that the Au islands covered with CVD diamond have a size in a few hundreds of nanometers and are oriented with diamond in the orientation relationship of {111}Au//{111}(Dia) and < 110 > Au//< 110 > Dia. The surfaces of the CVD diamond films grown on substrate with and without Au coating exhibit cracks when the film thickness reaches 3.5 mu m. As evaluated from the Raman peak shift, it is shown that the internal tensile stress in the film with Au islands is less than in the same thick film on substrate without Au coating. A crack-free (111) homoepitaxial diamond film in the same thickness can be obtained by insertion of multilayers of Au islands in CVD diamond. (c) 2015 Elsevier Ltd. All rights reserved.
Indium-rich InAlN films on GaN/sapphire by molecular beam epitaxy
(2014-03)
Wu, Yue-Han
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Wong, Yuen-Yee
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Chen, Wei-Chun
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Tsai, Dung-Sheng
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Peng, Chun-Yen
Here, we report the results of characterization of indium (In)-rich InAlN films on GaN/Sapphire (0001) substrates grown by molecular beam epitaxy. The highquality similar to 123 nm thick InAlN films with 85% In content without phase separation were assessed with x-ray diffraction and transmission electron microscopy (TEM) with x-ray energy dispersive spectroscopy. High-resolution TEM analysis reveals the relaxation at InAlN/GaN interface with misfit dislocations of 1.59 nm spacing. Finally, optical and electrical properties of the InAlN films are presented from absorption spectroscopy and Hall measurements.