Browsing by Author "Wu, Yu-Hsun"

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Antimonidation of ultrathin epitaxial aluminum nanofilms for metamorphic growth of Sb-based structures on GaAs substrates
(2020-04-01)
Wu, Yu-Hsun
;
Wu, Jenq-Shinn
;
Lin, Sheng-Di
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
The narrow-bandgap Sb-based semiconductors find their potential in various kinds of device applications such as high-speed, low-power transistors and mid-infrared diode lasers. However, epitaxial growth on the substrates that are commercially available in large sizes (for example, GaAs and Si) faces the fundamental challenge of lattice mismatch. Different from the conventional metamorphic growth employing a thick buffer, we adopt the approach of transforming an ultrathin epitaxial aluminum (Al) nanofilm into epitaxial AlSb to serve as the template for growth of antimonide structures. It is found that the process named "antimonidation" plays a critical role in Sb-based metamorphic growth. Our experimental results provide practical usefulness for growing semiconductor devices on lattice-mismatched substrates without using thick metamorphic buffer layers. (C) 2020 The Japan Society of Applied Physics
Nano- to atomic-scale epitaxial aluminum films on Si substrate grown by molecular beam epitaxy
(2019-10-01)
Tsai, Yi-Hsun
;
Wu, Yu-Hsun
;
Ting, Yen-Yu
;
Wu, Chu-Chun
;
Wu, Jenq-Shinn
We demonstrate nano-to atomic-scale epitaxial aluminum film growth on Si(111) substrate by molecular beam epitaxy. Excellent quality of these aluminum films, including sub-nanometer surface roughness, narrow linewidth of X-ray diffraction peak, clear transmission electron diffraction, and high optical reflectivity in ultra-violet, have been obtained with a reproducible growth recipe. The atomic-scale metallic aluminum film is formed by the self-limiting oxidation on the 3-nm-thick sample in air and the metallic state is confirmed with X-ray photoemission spectroscopy. Our work paves the way to future integration of aluminum-based plasmonic and superconducting devices on Si platform. (c) 2019 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Solution-processed small molecular electron transport layer for multilayer polymer light-emitting diodes
(2011-03-01)
Liu, Zong-You
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Tseng, Shin-Rong
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Chao, Yu-Chiang
;
Chen, Chun-Yu
;
Meng, Hsin-Fei
Solution-processed electron transport layers (ETL) have been fabricated by solution process and applied in multilayer polymer light-emitting diodes with tris[2-(p-tolyl)pyridine]iridium(III) blended in poly(vinylcarbazole) as the emissive layer. Three kinds of small molecular electron transport materials, including 2,2',2 ''-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)(TPBi),3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (TAZ), and 4,7-diphenyl-1,10-phenanthroline (BPhen), are tested and dissolved in methanol to form electron transport layers by blade coating. Such electron transport layer provides efficient electron injection and electron transport ability in the devices. The efficiency of the devices with the combination of ETL and LiF/Al cathode reaches 21.5 cd/A at 10 V (4050 cd/m(2)). The efficiency of the devices without ETL are 3.5 cd/A (13 V) for LiF/Al cathode and 17 cd/A (7 V) for CsF/Al cathode at 1000 cd/m(2). The aggregation of the solution-processed ETL can be controlled by annealing temperature to further optimize the device performance to maximal efficiency of 53 cd/A. (C) 2010 Elsevier B.V. All rights reserved.