由分子動力學模擬探討層狀石墨烯的成長與碳化矽基板上多層石墨烯的熱穩定性; Growth of layered graphene and the thermal stability of multilayered graphene on silicon carbide substrate by molecular dynamics simulation

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題名:	由分子動力學模擬探討層狀石墨烯的成長與碳化矽基板上多層石墨烯的熱穩定性;Growth of layered graphene and the thermal stability of multilayered graphene on silicon carbide substrate by molecular dynamics simulation
作者:	艾利南;Rizal Arifin
貢獻者:	物理研究所
關鍵詞:	石墨烯;分子動力學模擬;graphene;molecular dynamics simulation
日期:	2011-07-28
上傳時間:	2012-01-05 14:42:39 (UTC+8)
摘要:	我們使用了分子動力學模擬和模擬退火方法來研究石墨烯的磊晶成長過程和石墨烯納米帶(6H - SiC(0001))的熱穩定性質。為了理解其背後機制,我們使用了兩種勢能作為我們的參數 , 即目前廣泛被應用的 Tersoff 勢能 [Phys 。 Rev 。 B 39 , 5566 ( 1989 ) ] , 以及由 Erhart 和 Albe 提出的 Tersoff 勢能修正的版本 [Phys。 Rev。 B 71,035211-1(2005)]。我們發現,一般狀況下第二個版本的勢能在預測石墨烯開始成長在基板上的溫 ,會和實驗結果比較一致。我們分析了石墨度烯的碳原子平均鍵距,徑向分布函數,束縛能以及基板和石墨烯的間距來確認模擬結果的合理性。石墨烯結構出現的溫 1325K 和實驗上預測的溫度非常一致。至於度熱穩定度方面,我們分析了無限大石墨烯層在靠近 SiC 基板的一些表面型態學上的特性,和目前文獻上的結果是一致的。最後,我們得到了一個臨界退火溫度 , 2000K。如果系統溫度低於臨界溫度,石墨緩衝層會比較穩定。如果大於這個溫度, 緩衝層開始會有從基板向上傾斜的趨勢。 The molecular dynamics simulation and simulated annealing method were applied to study the growth process of graphene and the thermal stability of layered graphene nanoribbons on 6H-SiC(0001) substrate. With an intention to understand the mechanisms that govern these panoramas, we tested two empirical potentials, i.e. the widely used Tersoff potential [Phys. Rev. B 39, 5566 (1989)] and its more refined version published years later by Erhart and Albe [Phys. Rev. B 71, 035211-1 (2005)]. We found that the modified Tersoff potential communicated by Erhart and Albe is generally more banausic for growing layered graphene on 6H-SiC substrate for the annealing temperature at which the graphene structure comes into view is very close to that observed in epitaxially grown graphene experiments. We evaluate our grown layered graphene by checking the reasonableness of the average carbon-carbon bond- length, pair correlation function, binding energy and also comparing with the experimentally grown epitaxial graphene the distances among the overlaid layers of graphene and substrate surface. The annealing temperature we obtained at 1325 K at which the graphitic structure just comes into view is reasonably close to the experimentally observed pit formation. On the thermal stability of layered graphene, the characteristics of the surface morphology of an infinite graphene sheet that we positioned near SiC substrate are consistent with other simulation works. Most importantly we obtained a threshold annealing temperature at around 2000 K below which the structural behavior of the carbon buffer layer is thermally stable and above which one sees the graphitic structures show tendency to slant up from the substrate.
顯示於類別:	[物理研究所] 博碩士論文

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