Detection of H⁺ recoiled from Si(1 1 1)-1 脳 1-H by medium energy Ne⁺ impact

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• 作者：K. Mitsuhara ; H. Okumura ; T. Matsuda ; M. Tagami ; A. Visikovskiy ; Y. Kido ; ^{ykido@se.ritsumei.ac.jp}
• 关键词：Elastic recoil detection of H ; Si(1&#xA0 ; 1&#xA0 ; 1)&ndash ; 1&#xA0 ; × ; &#xA0 ; 1-H ; Medium energy Ne+ impact ; H+ fraction ; Zero-point energy ; Doppler broadening
• 刊名：Nuclear Instruments and Methods in Physics Research Section B ; Beam Interactions with Materials and Atoms
• 出版年：2012
• 期刊代码：42_0168583x
• 类别：ph
• 出版时间：1 April, 2012
• 卷：276
• 期：Complete
• 页码：56-61
• 文件大小：733 K

摘要

We detected the H⁺ ions recoiled from Si(1&#xA0;1 1)-1 脳 1-H by medium energy 80-150 keV Ne⁺ impacts. The H⁺ fraction is dependent on emerging angle and emerging energy. With decreasing the emerging angle scaled from the surface normal the H⁺ fraction increases and reaches a saturation below 鈭?0掳 and almost 100%for emerging energy above 13 keV. In contrast, the charge state is not equilibrated even at 鈭?5掳. Such strong dependence on emerging angle is due to the location of H bound by Si atoms on top of the surface. The sensitivity to H on the surfaces is estimated to be better than 5 脳 10¹² atoms/cm² at a small emerging angle (胃_out < 鈭?5掳), where the H⁺ fraction reaches 鈭?00%. The unexpectedly large energy spread for the recoiled H⁺ spectra is attributed to the Doppler broadening caused by the zero-point energy of the vibrating H-Si system and additionally to small energy transfers among the three bodies of Ne⁺ and H-Si, although the assumption of binary collision between Ne⁺ and H is approximately valid. This H detection technique can be widely applied to analysis of chemical reactions including adsorption and desorption mediated by water and hydroxyl on various kinds of metal-oxide surfaces.