Browsing by Author "Wu, Chu-Chun"

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Atomic-scale epitaxial aluminum film on GaAs substrate
(2017-07-01)
Fan, Yen-Ting
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Lo, Ming-Cheng
;
Wu, Chu-Chun
;
Chen, Peng-Yu
;
Wu, Jenq-Shinn
Atomic-scale metal films exhibit intriguing size-dependent film stability, electrical conductivity, superconductivity, and chemical reactivity. With advancing methods for preparing ultra-thin and atomically smooth metal films, clear evidences of the quantum size effect have been experimentally collected in the past two decades. However, with the problems of small-area fabrication, film oxidation in air, and highly-sensitive interfaces between the metal, substrate, and capping layer, the uses of the quantized metallic films for further ex-situ investigations and applications have been seriously limited. To this end, we develop a large-area fabrication method for continuous atomic-scale aluminum film. The self-limited oxidation of aluminum protects and quantizes the metallic film and enables ex-situ characterizations and device processing in air. Structure analysis and electrical measurements on the prepared films imply the quantum size effect in the atomic-scale aluminum film. Our work opens the way for further physics studies and device applications using the quantized electronic states in metals. (C) 2017 Author(s).
Epitaxial GaAs and pHEMT on aluminum-transformed AlAs nanofilms
(2018-09-01)
Cheng, Chia-Chu
;
Wu, Chu-Chun
;
Fan, Yen-Ting
;
Wu, Jenq-Shinn
;
Lin, Sheng-Di
Heterogeneous epitaxial growth between semiconductors and metals boosts novel device development and enables various applications. In this work, we have investigated the epitaxial growth of GaAs layers on top of a nanoscale aluminium-transformed AlAs film. The grown GaAs layers are single-crystalline and of highquality, that has been evidenced by using various material characterization methods and by fabricating their high-electron mobility transistors. We found that an intriguing process named as "arsenidation" of aluminium film plays a key role in the successful epitaxy. Our work opens a window for growing semiconductor/metal hetero-structures for various device applications in the future. (C) 2018 Author(s).
Growth of atomic-scale aluminum film on GaAs substrate
(2016)
Lo, Ming-Cheng
;
Fan, Yen-Ting
;
Wu, Chu-Chun
;
Chen, Peng-Yu
;
Lin, Sheng-Di
We present the method for large-area growth of single-crystalline Al films in atomic scale on GaAs substrate by using molecular beam epitaxy. The grown Al film of thickness down to 5 nm exhibits smooth surface morphology, a clear and single X-ray diffraction peak in. theta-2 theta scan, and nearly transparent optical response. This work open a window for ex-situ studying quantum size effect in metal film.
High-quality GaAs grown on aluminum film
(2017-01-01)
Cheng, Chia-Chu
;
Wu, Chu-Chun
;
Fan, Yen-Ting
;
Lin, Sheng-Di
;
電機學院
We have grown GaAs layers on an aluminum nanofilm by using molecular beam epitaxy. Defect-free GaAs and InAs quantum dots are investigated with X-ray diffraction, transmission electron microscopy, and room-temperature photoluminescence.
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/).
Nano-scale oxide layer prepared by plasma oxidation on single-crystalline aluminum film
(2016)
Chen, Peng-Yu
;
Wu, Chu-Chun
;
Fan, Yan-Ting
;
Lin, Sheng-Di
;
電子工程學系及電子研究所
The plasma oxidation on single crystalline Al thin film grown by molecular beam epitaxy is presented. The dependence of oxidation rates on the N2O flux, the substrate temperature, the RF power, and the chamber pressure is studied with auger electron spectroscopy and transmission electron microscope. Our work provides a simple way to prepare a smooth nano-scale Al(2)O(3 f)ilm on aluminum, which is a key step to fabricate ultraviolet plasmonic nanolasers.