鑽石表面的氫化學

Hydrogen Chemistrry on Diamond Surfaces

10.6623/chem.2002043

蘇昭瑾(Chaochin Su)；林景泉(Jiing-Chyuan Lin)

鑽石 ； 單晶表面 ； 氫化反應 ； 超高真空系統 ； 低能電子繞射儀 ； 程式控溫熱脫附光譜法 ； diamond ； C(111) ； single crystal surface ； hydrogenation ； UHV ； LEED ； TPD

化學

60卷3期（2002 / 09 / 01）

449 - 456

繁體中文

本文主要在闡述鑽石C(111)單晶表面上氫的吸附及脫附反應。利用低能電子繞射儀(LEED)及程序控溫熱脫附法(TPD)，在超高真空(UHV)下探討氫在吸附過程中C(111)表面結構的變化及氫分子脫附動力學。我們發現，氫吸附在C(111)面時會聚集形成高度氫化區域，並由(2x1)重構表面轉回(1x1)的原始鍵結結構。氫分子為唯一的熱脫附產物。氫脫附時表面之氫化區域會隨之收縮使保持高氫化區域的狀態。脫附反應為一次反應，活化能在大部分氫的覆蓋度下為3.7電子伏特。這些結果及所提模型幫助我們瞭解鑽石薄膜成長過程中氫所扮演之角色及反應過程，並希望能提供鑽石薄膜成長最佳化條件所須的有效資訊。

Hydrogen chemistry plays an important role in diamond film technology. The hydrogen chemisorption and thermal desorption on the diamond C(111) surface have been studied using low energy electron diffraction (LEED) and temperature programmed desorption (TPD) techniques in ultra-high vacuum (UHV) system. It was found that during adsporption, hydrogen atoms segregate to form highly hydrogenated domains from where hydrogen atoms recombine and deorb concerted as the substrate surface is heated up. The molecular hydrogen desorption from the C(111) surface exhibits the first-order kinetics with a nearly coverage-independent activation energy of 3.7 eV. From the quantitative analysis of diffraction spots intensity on the as-dosed, partially desorbed, and annealed hydrogenated C(111) surfaces, the correlation between structure transformation, hydrogen coverage, and surface temperature is shown. Those results provide important information needed to optmize the parameters for the growth of diamond thin film.