磊晶成長之大面積二維材料及其元件應用

Large-Area Epitaxially Grown Two-Dimensional Crystals and Their Device Applications

林孟佑(Meng-Yu Lin)

指導教授 ： 李嗣涔

共同指導教授 ： 林時彥(Shih-Yen Lin)

國立臺灣大學/電機資訊學院/電子工程學研究所/博士(2015年)

https://doi.org/10.6342/NTU.2015.00882

摘要

本論文將利用不同的成長方式來探討大面積二維材料的的成長機制。在石墨烯成長方面，利用分子束磊晶法於石墨烯的成長過程中直接提供(沉積)碳原子於基板表面。大面積的石墨烯可於較低的成長溫度分別於金屬表面或是具氧化層之基板表面形成。我們另外利用化學氣相沉積法來增加石墨烯成長時的碳量，並成功直接在藍寶石基板上製備出大面積、均勻且高品質的石墨烯薄膜。同時，也利用化學氣相沉積法，於藍寶石基板上分別製備出大面積且可層數控制的二硫化鉬薄膜與二硫化鉬/石墨烯異質結構薄膜。如此新穎的異質結構製備方式，將會使得許多對於單一二維材料上的橫向載子傳輸特性轉向縱向的異質結構元件特性。針對石墨烯元件的探討，我們試著以元件結構的方式調變石墨烯通道的費米能階。利用側向電極或雙切痕通道的結構，通道的費米能階會隨著我們施加的側向電場或切痕間距來做改變。另外，利用二硫化鉬與石墨烯行程的異質結構，光激發電子會由二硫化鉬流向石墨烯，進而產生石墨烯通道的費米能階變化。

關鍵字

石墨烯 ； 二硫化鉬 ； 分子束磊晶法 ； 化學氣相沉積法 ； 異質結構

並列摘要

Different approaches are adopted for epitaxially grown large-area 2-D crystals in this thesis. For graphene growth, by using the molecular beam epitaxy (MBE) technique to directly supply carbon atoms during the growth, the growth temperature of the graphene films can be greatly reduced on either metal template or dielectric substrate surfaces. After increasing the carbon source amount by using chemical vapor deposition (CVD) technique, epitaxially grown 2-D crystals such as graphene, MoS2 and MoS2/graphene hetero-structures can be obtained directly on sapphire substrates. The advances of 2-D crystal hetero-structures would move the focus of current researches from lateral carrier transport behaviors of single 2-D material to those on vertical 2-D crystal hetero-structures. For device applications, the Fermi level tuning of the graphene transistors is studied by using lateral gates and dual-cuts channel architectures. By using the atomic force microscope tip scrapping on the graphene surface, these devices can be easily fabricated and show tunable Fermi levels. Photo-induced Fermi level shift is also observed on transistors fabricated with MoS2/graphene hetero-structures.

並列關鍵字

Graphene ； MoS2 ； Chemical Vapor Deposition ； Molecular Beam Epitaxy ； Hetero-structures

參考文獻

[2] L. D. Landau, “Zur Th Eorie Der Phasenumwandlungen II”, Phys. Z. Sowjetunion, vol. 11, pp. 26–35, 1937.

[4] L. M. Malard, M. A. Pimenta, G. Dresselhaus, M. S. Dresselhaus, “Raman Spectroscopy in Graphene”, Phys. Rep., vol. 473, pp. 51-87, March 2009.

[6] G. Jo, M. Choe, C.-Y. Cho, J. H. Kim, W. Park, S. Lee, W.-K. Hong, T.-W. Kim, S.-J. Parl, B. H. Hong, Y. H. Kahng, and T. Lee “Large-area Patterned Multi-layer Graphene Films as Transparent Conducting Electrodes for GaN Light-emitting Diodes”, Nanotechnol., vol. 21, pp. 175201, April 2010.

[8] J. H. Chen, C. Jang, S. Xiao, M. Ishigami, and M. S. Fuhrer, “Intrinsic and extrinsic performance limits of graphene devices on SiO2”, Nature Nanotech., vol. 3, pp. 206–209, March 2008.

[9] E. H. Hwang, B. Y.-K. Hu, and S. D. Sarma, “Inelastic carrier lifetime in graphene”, Phys. Rev. B, vol. 76, pp. 115434, December 2007.