Browsing by Author "Wei, Lin-Lung"

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2H-Silicon Carbide Epitaxial Growth on c-Plane Sapphire Substrate Using an AlN Buffer Layer and Effects of Surface Pre-Treatments
(2015-05-01)
Luong, Tien-Tung
;
Binh Tinh Tran
;
Ho, Yen-Teng
;
Wei, Ting-Wei
;
Wu, Yue-Han
The effects of surface pre-treatments and the role of an AN buffer layer for 2H-SiC growth on c-plane sapphire substrates by thermal CVD are investigated. While the crystallinity of SiC directly grown on sapphire substrate always degrades with a hydrogen pre-treatment but improves by optimizing carbonization, the crystallinity of SiC grown on sapphire substrate using an AN buffer grown by MOCVD improves with sufficient time of exposure to the H pre-treatment but always deteriorates with carbonization. Detailed microstructural analysis by phi-scan x-ray diffraction reveals that SiC film grown on sapphire substrate consists of crystalline domains with two different crystallographic orientations which are rotated relative to each other along the [111] axis by 60 degrees. A highly oriented hexagonal 2H-SiC film is obtained on low-cost c-plane sapphire substrate by using an AN buffer. 2H-SiC is unambiguously determined not only by phi-scan x-ray diffraction but also by high-resolution transmission electron microscopy. The growth relationship between 2H-SiC and 2H-AlN are coherent due to the favorable bonding of C and Al between SiC and AlN.
Atomically resolved interface structure between epitaxial TiN film and MgO substrate
(2016-11-01)
Wei, Lin-Lung
;
Yen, Tzu-Chun
;
Do, Hien
;
Chang, Li
;
材料科學與工程學系
In this study, we used a high quality epitaxial TiN thin film grown on MgO (001) substrate for the investigation of the TiN/MgO interface structure which was characterized with scanning transmission electron microscopy (STEM) at atomic resolution. Analyses of high angle annular dark-field and annular bright-field STEM image contrast with X-ray energy dispersive spectroscopy maps show that a 2-4 nm diffuse interlayer of mixed compositions exists coherently between TiN and MgO with the same structure and across the interface the ionic bonding sequences are maintained without any interruption. (C) 2016 Elsevier B.V. All rights reserved.
Atomically resolved interface structure between epitaxial TiN film and MgO substrate
(2016-11-01)
Wei, Lin-Lung
;
Yen, Tzu-Chun
;
Do, Hien
;
Chang, Li
;
材料科學與工程學系
In this study, we used a high quality epitaxial TiN thin film grown on MgO (001) substrate for the investigation of the TiN/MgO interface structure which was characterized with scanning transmission electron microscopy (STEM) at atomic resolution. Analyses of high angle annular dark-field and annular bright-field STEM image contrast with X-ray energy dispersive spectroscopy maps show that a 2-4 nm diffuse interlayer of mixed compositions exists coherently between TiN and MgO with the same structure and across the interface the ionic bonding sequences are maintained without any interruption. (C) 2016 Elsevier B.V. All rights reserved.
Epitaxial single-crystal of GaSe epilayers grown on a c-sapphire substrate by molecular beam epitaxy
(2015-10-01)
Wu, Chia-Hsin
;
Yang, Chu-Shou
;
Wang, Yen-Chi
;
Huang, Hsi-Jung
;
Ho, Yen-Teng
In this study, hetero-epitaxy of GaSe epilayers on a c-sapphire substrate achieved using molecular beam epitaxy was demonstrated. The GaSe epitaxial growth was monitored using in situ reflection high-energy electron diffraction (RHEED). Streak RHEED patterns showed a flat and highly crystalline situation. Furthermore, two RHEED patterns were observed after 15min of growth, and they were correlated with the m-axis and a-axis of hexagonal GaSe. The single crystal of GaSe was verified using X-ray diffraction and high-resolution cross-section transmission electron microscopy. The full width at half-maximum of (0002) in the XRD rocking-curve spectrum of GaSe epilayer is obtain around 207arcsec, which is the smallest value observed to date. The epitaxial growth of GaSe demonstrated the feasibility of growing large-area epilayers.
Formation of m-plane AlN on plasma-nitrided m-plane sapphire
(2019-06-01)
Ma, Zhih-Cheng
;
Chiu, Kun-An
;
Wei, Lin-Lung
;
Chang, Li
;
材料科學與工程學系
Microwave plasma using a gas mixture of N-2 and H-2 has been applied for the nitridation of m-plane sapphire substrate to form a thick epitaxial AlN film. The X-ray diffraction results show that the AlN films formed on the sapphire surface by nitridation for a period from 10-60 min are in (1010) orientation and have an epitaxial relationship with the substrate. The thickness of the nitride film increases with nitridation time and approaches about 0.5 mu m after nitridation for 1 h, while the film surface becomes rough. The film quality is reasonably good, as evaluated with the X-ray rocking curve of (1010) AlN. Faceted voids in the sapphire substrate underneath the AlN are also observed with inclined a-plane facets after nitridation. (C) 2019 The Japan Society of Applied Physics
Layered MoS2 grown on c-sapphire by pulsed laser deposition
(2015-03-01)
Ho, Yen-Teng
;
Ma, Chun-Hao
;
Luong, Tien-Tung
;
Wei, Lin-Lung
;
Yen, Tzu-Chun
Layered growth of molybdenum disulphide (MoS2) was successfully achieved by pulsed laser deposition (PLD) method on c-plane sapphire substrate. Growth of monolayer to a few monolayer MoS2, dependent on the pulsed number of excimer laser in PLD is demonstrated, indicating the promising controllability of layer growth. Among the samples with various pulse number deposition, the frequency difference (A1gE12g) in Raman analysis of the 70 pulse sample is estimated as 20.11 cm(1), suggesting a monolayer MoS2 was obtained. Two-dimensional (2D) layer growth of MoS2 is confirmed by the streaky reflection high energy electron diffraction (RHEED) patterns during growth and the cross-sectional view of transmission electron microscopy (TEM). The in-plane relationship, (0006) sapphire//(0002) MoS2 and inline image sapphire//inline imageMoS(2) is determined. The results imply that PLD is suitable for layered MoS2 growth. Additionally, the oxide states of Mo 3d core level spectra of PLD grown MoS2, analysed by X-ray photoelectron spectroscopy (XPS), can be effectively reduced by adopting a post sulfurization process. (C) 2015 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim
Orientations of ZnO grown on GaN(10(1)over-bar1)
(2015-01-01)
Shih, Yi-Sen
;
Lin, Pei-Yi
;
Wei, Lin-Lung
;
Chang, Li
;
材料科學與工程學系
On semipolar GaN(10 (1) over bar1), epitaxial ZnO grown by chemical vapor deposition consists of two distinct orientations as evidenced by transmission electron microscopy and X-ray diffraction. The initially grown ZnO on GaN follows the GaN lattice with the epitaxial relationship of ZnO(10 (1) over bar1)//GaN(10 (1) over bar1) and ZnO GaN [1 (2) over bar 10](ZnO)//[1 (2) over bar 10](ZnO). The other oriented ZnO domains then grow on faceted (10 (1) over bar1) ZnO with ZnO(0002)//ZnO(10 (1) over bar1) and [(2) over bar 110](ZnO)//[1 (1) over bar0 (1) over bar](ZnO) with good coherency with the (10 (1) over bar1) -oriented grains. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
POST SULFURIZATION EFFECT ON THE MOS2 GROWN BY PULSED LASER DEPOSITION
(2016)
Ho, Yen-Teng
;
Yen, Tzu-Chun
;
Luong, Tien-Tung
;
Wei, Lin-Lung
;
Tu, Yung-Yi
Two inches size with high quality layered growth of MoS2 was achieved by PLD on c-plane sapphire substrate. 2-3 monolayer MoS2 was obtained within 2 inches wafer estimated from Raman analysis and confirmed by cross-sectional view of TEM. Additionally, the oxide states of Mo 3d core level spectra of MoS2, analyzed by XPS, can be effectively reduced by adopting a post sulfurization process in H2S. The post process also improve the photoluminescence (PL) of MoS2 as well as the electrical characteristic of MoS2 FET due to elimination the Mo oxide in the grown film.
Single domain non-polar (12(3)over-bar0)ZnO epitaxy on (118)LaAlO3 by pulsed laser deposition
(2016-11-01)
Yen, Tzu-Chun
;
Ho, Yen-Teng
;
Peng, Chun-Yen
;
Tian, Jr-Sheng
;
Shih, Yi-Sen
An unconventional non-polar (12 (3) over bar0)ZnO epitaxial film is grown on (118)LaAlO3(LAO) substrate by pulsed laser deposition. X-ray diffraction pole figures and transmission electron microscopy show that the crystal orientation relationships between non-polar (1230)ZnO and (118)LAO substrate are (0001)ZnO // (110)LAO and (1120)ZnO // (001)LAO. The Raman spectrum with a significant E2 peaked at 439 cm(-1) clearly indicates the formation of non-polar ZnO film. Photoluminescence measurement of the non-polar ZnO film shows a strong near band-edge emission located at 3.3 eV with negligible green-yellow emission. (C) 2016 Elsevier B.V. All rights reserved.
Single domain non-polar (12(3)over-bar0)ZnO epitaxy on (118)LaAlO3 by pulsed laser deposition
(2016-11-01)
Yen, Tzu-Chun
;
Ho, Yen-Teng
;
Peng, Chun-Yen
;
Tian, Jr-Sheng
;
Shih, Yi-Sen
An unconventional non-polar (12 (3) over bar0)ZnO epitaxial film is grown on (118)LaAlO3(LAO) substrate by pulsed laser deposition. X-ray diffraction pole figures and transmission electron microscopy show that the crystal orientation relationships between non-polar (1230)ZnO and (118)LAO substrate are (0001)ZnO // (110)LAO and (1120)ZnO // (001)LAO. The Raman spectrum with a significant E2 peaked at 439 cm(-1) clearly indicates the formation of non-polar ZnO film. Photoluminescence measurement of the non-polar ZnO film shows a strong near band-edge emission located at 3.3 eV with negligible green-yellow emission. (C) 2016 Elsevier B.V. All rights reserved.
Structure of coherent Mg3TiO4 oxide formed between TiN and MgO
(2018-02-15)
Wei, Lin-Lung
;
Chang, Li
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Solid state reaction in nanometer scale at the interface between TiN and MgO can result in formation of Mg3TiO4 particles which has not reported before. The structure of the newly found oxide is characterized with spherical-aberration corrected scanning transmission electron microscopy at atomic resolution with X-ray energy dispersive spectroscopy. The nanosized Mg3TiO4 oxide particles formed in MgO underneath the epitaxial TN film with cube-on-cube coherent relationship with both MgO and TiN, i.e. TiN(0 0 1) parallel to Mg-Ti-O(0 0 1) parallel to MgO(0 0 1) and TiN[1 1 0] parallel to| Mg-Ti-O[1 1 0] parallel to MgO[1 1 0]. Mg3TiO4 is identified to have cubic structure (lattice parameter a = 0.842 nm) with space group of Fd (3) over barm. (C) 2017 Elsevier B.V. All rights reserved.
WAFER SIZE MOS2 WITH FEW MONOLAYER SYNTHESIZED BY H2S SULFURIZATION
(2017-01-01)
Ho, Yen-Teng
;
Chu, Yung-Ching
;
Wei, Lin-Lung
;
Luong, Tien-Tung
;
Lin, Chih-Chien
Wafer sized, high quality continuous fihns would be a key demand for MoS2 implemented in circuit application. In this study, the growth of few monolayer Mo-S2 on 4 inches SiO2/Si substrate were demonstrated. The MoS2 thin films were synthesized by sulfurized in a furnace from the ultra-thin MoO3 starting materials by using H2S. The obtained MoS2 thin film examined by Raman analysis and Photoluminescence (PL), shows the semiconductor nature with direct transition peaks of 1.86 eV and 1.99 eV. The 4 5 monolayer of MoS2 with thickness around 2.6 nm is confirmed by cross-sectional view of transmission electron microscopy (TEM). Additionally, the DC characteristics of MoS2 MOSFETs exhibit at least 2 order in on/off current ratio, demonstrating the feasibility for circuit application.