レーザー励起による半導体表面構造の不安定性

抄録

A scanning tunneling microscopy study, combined with high-sensitive detection of desorbed neutral species, has revealed that laser-light excitation induces electronic bond breaking of constituent atoms at intrinsic sites on covalent semiconductor surfaces. The bond breaking forms vacancies at individual surface sites, and leads to desorption of atoms in the electronic ground state with translational energies characteristic of electronic process. The bond-breaking rate shows prominent site- and species-dependent effects, and depends super-linearly on the excitation density. The excited species responsible for the electronic process has been identified to be valence holes, and the characteristics experimentally observed are explained reasonably in terms of two-hole localization.