蘇維彬
Wei-Bin Su
886-2-2789-6711(O); 2789-8349, 2789-8318(Lab)
886-2-2783-4187
wbsu@phys.sinica.edu.tw
學 / 經歷
- 清華大學物理系博士 (1996)
- 東海大學物理系學士 (1990)
- 中央研究院物理所助研究員 (2001)
- 中央研究院物理所博士後 (1996)
研究領域
- 金屬薄膜磊晶成長
- 低溫超高真空掃描穿隧顯微與能譜術
- 量子尺寸效應
- 表面電性結構量測
研究興趣與成果
我們最近的研究主要在利用超高真空低溫掃描穿隧顯微與能譜術探討金屬薄膜中的量子尺寸效應。例如我們可以在鉛薄膜觀察到量子井態以及在銀薄膜觀察到穿透共振。所謂的量子井態是指電子被局限在鉛薄膜中的位能井,由於電子具有波性,電子的波向量在垂直於薄膜的方向被量子化,造成電子在薄膜中會形成駐波以及所對應的能態是分離的量子井態。量子井態是束縛態,因此出現在真空能階以下。穿透共振則是指電子被銀薄膜中的位能井散射,也是由於波性,電子的穿透率會隨入射能量而呈現振盪的現象,在電子的穿透率最高時就稱為穿透共振。穿透共振是量子散射現象,因此出現在真空能階以上。此外在真空能階以上也可觀察到場發射共振現象,這是由於電子在掃描穿隧顯微儀中的探針-樣品間隙中形成駐波態,導致探針中的電子需透過駐波態才能場發射。場發射共振也是一種量子尺寸效應,也被稱作昆拉赫振盪。以下是我們最近的成果 :
鏡像位能於未填滿量子井態的相位貢獻
先前利用掃描穿隧顯微術(STM)研究金屬薄膜中的量子井態的研究,都關注在費米能階附近+-2 電子伏特的能量範圍中的量子井態。這些先前的研究顯示利用量子力學中的方形位能井模型可以清楚了解這能量範圍的量子井態的能階。我們利用STM中的Z-V能譜術觀察鉛薄膜中於費米能階以上2-5電子伏特的未填滿量子井態。發現到在這能量範圍的量子井態的能階會受到鏡像位能的影響,造成量子井態無法單純用方形位能井模型解釋。我們利用相位累積模型並在模型中引進鏡像位能的相位貢獻,成功解釋較高能量的量子井態的行為。此外,我們從相位累積模型的結果得到一有趣且重要的結論:在鉛薄膜外會存在一量子區域,鏡像位能在此區域會消失。由於存在著量子區域,當電子在金屬表面時,才不會出現鏡像位能發散成無窮大的狀況。此成果已發表在Physical Review Letters 102, 196102 (2009)。
功函數差異於高階昆拉赫振盪峰之呈現
當金屬薄膜的厚度在奈米的尺度時,薄膜的電性結構會受到量子尺寸效應的影響,進而使金屬薄膜的功函數隨厚度而變化。此課題在奈米科學上有其重要性,因為人們可以藉由量測功函數進而理解薄膜的電性結構。功函數是金屬中的電子要離開金屬所需克服的能量,一般可以利用光電子能譜量測。然而此技術是以光激發出電子,所用光源會涵蓋整個薄膜,因此薄膜的厚度必須要均勻,否則所量測的結果是多種厚度的功函數的平均值。所以薄膜的成長必須要是一層接一層的模式,才適合用光電子能譜,然而有很多薄膜系統的成長是不均勻的。為了克服這個限制,可以利用局部探測技術如掃描穿隧顯微儀,此技術不需要薄膜是均勻的成長。人們可以利用掃描穿隧顯微儀量測電子穿隧所面對的位能障礙,此物理量會與功函數相關。然而利用此方法量測的功函數的誤差高達0.3電子伏特,其精確度遠低於光電子能譜。
我們發現利用掃描穿隧顯微儀中的高階昆拉赫振盪的尖峰特徵可以對金屬薄膜的功函數作精確量測,其誤差可低於0.02電子伏特,精確度直逼光電子能譜。由於這是一技術上的突破,所以此成果發表在物理評論通訊(Phys. Rev. Lett. 99, 216103, (2007))。由於此技術具有高精確度,因此可以量測出某些奈米結構的功函數的微細差異,進而理解奈米結構不同的電性以及其中的物理,因此我們的發現為奈米科學的研究提供了新的方法。
Selected Recent Publications
- Yann Girard *, Sarah Benbouabdellah, Outhmane Chahib, Cyril Chacon, Amandine Bellec, Vincent Repain, Jérôme Lagoute, Yannick J. Dappe, César González, Wei-Bin Su, 2023, “Growth and local electronic properties of Cobalt nanodots underneath graphene on SiC(0001)”, Carbon, 208, 22.
- Wei-Bin Su*, Shin-Ming Lu, Ho-Hsiang Chang, Horng-Tay Jeng*, Wen-Yuan Chan, Pei-Cheng Jiang, Kung-Hsuan Lin, and Chia-Seng Chang, 2022, “Impact of band structure on wave function dissipation in field emission resonance”, Physical Review B, 105, 195411.
- Shitha Valsan Korachamkandy, Shin-Ming Lu, Wei-Bin Su*, Wen-Yuan Chan, Ho-Hsiang Chang, Horng-Tay Jeng, Chih-Hao Lee, and Chia-Seng Chang, 2022, “Probing tip-induced attractive deformation of graphite surfaces through wave function dissipation in field emission resonance”, Journal of Physics Communications 6, 075010.
- Shitha Valsan Korachamkandy, Shin-Ming Lu, Wen-Yuan Chan, Ho-Hsiang Chang, Chih-Hao Lee, Wei-Bin Su*, 2022, “Characterization of apex structures of scanning tunneling microscope tips with field emission resonance energies”, Japanese Journal of Applied Physics 61, 085001
- Wei-Bin Su*, Shin-Ming Lu, Horng-Tay Jeng, Wen-Yuan Chan, Ho-Hsiang Chang, Woei Wu Pai, Hsiang-Lin Liu and Chia-Seng Chang, 2020, “Observing quantum trapping on MoS2 through the lifetimes of resonant electrons: revealing the Pauli exclusion principle”, Nanoscale Advances, 2, 5848.
- Shin-Ming Lu, Wen-Yuan Chan, Wei-Bin Su*, Woei Wu Pai, Hsiang-Lin Liu and Chia-Seng Chang, 2018, “Characterization of external potential for field emission resonances and its applications on nanometer-scale measurements”, New Journal of Physics, 20, 043014.
- Wen-Yuan Chan, Shin-Ming Lu, Wei-Bin Su*, Chun-Chieh Liao, Germar Hoffmann, Tsong-Ru Tsai, and Chia-Seng Chang, 2017, “Sharpness-induced energy shifts of quantum well states in Pb islands on Cu(111)”, Nanotechnology, 28, 095706.
- Wei-Bin Su*, Chun-Liang Lin, Wen-Yuan Chan, Shin-Ming Lu, and Chia-Seng Chang, 2016, “Field enhancement factors and self-focus functions manifesting in field emission resonances in scanning tunneling microscopy”, Nanotechnology, 27, 175705.
- Kung-Hsuan Lin*, Shao-Wei Weng, Po-Wei Lyu, Tsong-Ru Tsai, and Wei-Bin Su*, 2014, “Observation of optical second harmonic generation from suspended single-layer and bi-layer graphene”, Applied Physics Letters, 105, 151605.
- Shao-Wei Weng, Wei-Hsiang Lin, Wei-Bin Su*, En-Te Hwu, Peilin Chen, Tsong-Ru Tsai and Chia-Seng Chang, 2014, “Estimating Young’s modulus of graphene with Raman scattering enhanced by micrometer tip”, Nanotechnology, 25, 255703.
- W. Y. Chan, H. S. Huang, W. B. Su*, W. H. Lin, H.-T. Jeng, M. K. Wu, and C. S. Chang , 2012, “Field-Induced Expansion Deformation in Pb Islands on Cu(111): Evidence from Energy Shift of Empty Quantum-Well States”, Physical Review Letters, 108, 146102.
- M. C. Yang, C. L. Lin, W. B. Su*, S. P. Lin, S. M. Lu, H. Y. Lin, C. S. Chang, W. K. Hsu, and Tien T. Tsong, 2009, "Phase Contribution of Image Potential on Empty Quantum Well States in Pb Islands on Cu(111) Surface", Phys. Rev. Lett., 102, 196102.
- C. L. Lin, S. M. Lu, W. B. Su*, H. T. Shih, B. F. Wu, Y. D. Yao, C. S.Chang, and Tien T. Tsong, 2007, "Manifestation of Work Function Difference in High Order Gundlach Oscillation", Phys. Rev. Lett., 99, 216103.
- W. B. Su*, S. M. Lu, C. L. Lin, H. T. Shih, C. L. Jiang, C. S. Chang, and Tien T. Tsong, 2007, "Interplay between transmission background and Gundlach oscillation in scanning tunneling spectroscopy", Phys. Rev. B, 75, 195406.
- S. M. Lu, M. C. Yang, W. B. Su*, C. L. Jiang, T. Hsu, C. S. Chang, and Tien T. Tsong, 2007, "Strength modulation of quantum-well states in Pb islands with periodic distortions on Si(111)", Phys. Rev. B, 75, 113402
- W. B. Su*, S. M. Lu, C. L. Jiang, H. T. Shih, C. S. Chang, and Tien T. Tsong, 2006, "Stark Shift of Transmission Resonance in Scanning Tunneling Spectroscopy", Phys. Rev. B, 74, 32767.
- W. B. Su*, S. M. Lu, H. T. Shih, C. L. Jiang, C. S. Chang, and Tien T. Tsong, 2006, "Manifestation of quantum size effect in transmission resonance", Journal of Physics: Condensed Matter, 18, 6299-6305.
- W. B. Su*, H. Y. Lin, Y. P. Chiu, H. T. Shih, T. Y. Fu, Y. W. Chen, C. S. Chang, and Tien T. Tsong, 2005, "Correlation between morphological transition and preferred thickness of Pb and Ag islands on Si(111)7X7", Phys. Rev. B, 71, 073304.
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