Hydrogen-related structural changes on CVD diamond (1 0 0) surfaces by ultra-high-vacuum annealing
Hydrogen-related structural changes on CVD diamond (1 0 0) surfaces by ultra-high-vacuum annealing
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超高真空退火 CVD 金刚石 (1 0 0) 表面与氢相关的结构变化
DOI：
10.1016/s0169-4332(03)00509-9
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Tsuyohito Ito
中科院分区：
文献类型：
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作者：
J. Nakamura;S. Fukumoto;T. Teraji;H. Murakami;Tsuyohito Ito
使用超高真空 (UHV) 扫描隧道显微镜 (STM)，我们研究了通过微波等离子体 (MWP) 化学气相沉积 (CVD) 方法同质外延生长的单晶 (100) 金刚石的表面原子结构。从 B 掺杂（p 型）生长（H 端接）金刚石样品中获取的 STM 图像显示出部分非晶状结构和与 H 端接金刚石 (100) 的 (2×1)/(1×2) 结构特征相关的部分不清楚的特征。虽然后者的结构随着远低于 500°C 的特高压退火处理的时间和温度的增加而变得更加清晰，但只有在高于 500°C 的充分退火后才能获得基本上清晰的 (2×1)/(1×2) 结构图像。在 150–200°C 进行适度的 UHV 退火有时会导致在 (2×1)/(1×2) 结构旁边的非常有限的区域中出现无序的短程 (3×1) 结构，其特征是行间距为 0.35 和 0.40 nm。这些观察结果表明，在最上表面存在 CH 和 CH2 键，在 UHV 退火和 CH 键的最终表面占据过程中，CH 和 CH2 物质的表面分数发生微小但可能的变化。此外，还讨论了 (2×1) 结构的占据和未占据状态的 STM 图像与表面 CH 键的成键和反成键状态的不同特征。
Using an ultra-high-vacuum (UHV) scanning tunneling microscope (STM), we have investigated surface atomic structures of single-crystalline (100) diamond homoepitaxially grown by means of a microwave-plasma (MWP) chemical-vapor-deposition (CVD) method. STM images taken from B-doped (p-type) as-grown (H-terminated) diamond samples showed partially amorphous-like structures and partially unclear features related to (2×1)/(1×2) structures characteristic of H-terminated diamond (100). While the latter structures became clearer with increasing periods and temperatures of UHV annealing treatments well below 500°C, substantially clear (2×1)/(1×2) structure images were obtained only after a sufficient annealing above 500°C. A moderate UHV annealing at 150–200°C sometimes resulted in the presence of disordered short-range (3×1) structures featured by row separations of 0.35 and 0.40nm in very limited areas beside the (2×1)/(1×2) structures. These observations suggest the existence of both CH and CH2bonds at the topmost surfaces, substantially small but possible changes in surface fractions of the CH and CH2species during the UHV annealing and the final surface occupation of the CH bonds. In addition, STM images differently featured for both occupied and unoccupied states of the (2×1) structure are discussed in relation to bonding and anti-bonding states of the surface CH bonds.