Laser-induced electronic bond breaking and structural changes on semiconductor surfaces
Laser-induced electronic bond breaking and structural changes on semiconductor surfaces
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激光诱导半导体表面电子键断裂和结构变化
DOI：
10.1117/12.352723
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
J. Kanasaki
中科院分区：
文献类型：
--
作者：
K. Tanimura;J. Kanasaki
本文综述了能量密度低于熔化和烧蚀阈值的ns和fs激光辐照Si（111）-（7 X7）和InP（110）-（1X 1）清洁表面引起的键断裂和结构变化。扫描隧道显微镜（STM）对辐照表面的原子成像表明，Si（111）-（7 X7）吸附原子的键断裂是由电子过程引起的，主要在单个吸附原子位置形成吸附原子空位。Si原子在电子基态解吸的峰值平移能量为0.06 eV，作为一个直接后果的键断裂。另一方面，辐照InP（110）-（1X 1）表面的STM图像显示了最顶部的P原子的优先去除，具有由准一维P行上的几个相邻空位组成的空位串的显著形成产率。孤立的In空位也形成，但产量小得多。对于这两种表面，键断裂发生在表面结构的本征位点，并且效率是强烈的位点敏感的，共振波长依赖的，并且相对于激发强度高度超线性。电子键断裂是由表面电子态中激发态的非线性局域化引起的。
We review the bond breaking and structural changes on clean surfaces of Si(111)-(7X7) and of InP(110)-(1X1) induced by ns- and fs-laser irradiation with fluences below thresholds of melting and ablation. Atomic imaging of the irradiated surface by scanning tunneling microscopy (STM) has shown that the bond breaking of adatoms of Si(111)- (7X7) is induced by an electronic process to form adatom vacancies mostly at individual adatom sites. Si atoms in the electronic ground state are desorbed with a peak translational energy of 0.06 eV, as a direct consequence of the bond breaking. On the other hand, STM images of the irradiated InP(110)-(1X1) surfaces have revealed the preferential removal of the top-most P atoms, with significant formation yields of vacancy strings consisting of several adjacent vacancies on the quasi-one dimensional P rows. The isolated In vacancies are also formed, but with a much smaller yield. For both surfaces, bond breaking takes place at intrinsic sites of the surface structures, and the efficiency is strongly site-sensitive, resonantly wavelength-dependent, and highly super-linear with respect to the excitation intensity. The electronic bond breaking is shown originate from non-linear localization of excited species in surface electronic states.