2007 Fiscal Year Final Research Report Summary
Structural instabilities of semiconductor surfaces by low energy electron beam
| Project/Area Number |
17540295
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics I
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| Research Institution | Osaka University |
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Principal Investigator |
KANASAKI Junichi Osaka University, The Institute of Scientific and Industrial Research, Associate Professor (80204535)
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| Co-Investigator(Kenkyū-buntansha) |
TANIMURA Katsumi Osaka University, The Institute of Scientific and Industrial Research, Professor (00135328)
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| Project Period (FY) |
2005 – 2007
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| Keywords | semiconductor surfaces / electronic excitation / low energy electron beam / carrier injection / bond breaking / scanning tunneling microscope |
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| Research Abstract |
We studied the structural responses of semiconductor surfaces induced by low energy electron (LEE) beams with high energy resolution (0.3eV), to understand completely the primary mechanisms of the LEE interaction with solids. Obtained results are as follows :
1) We have demonstrated that the LEE-beam induced bond rupture on the Si (001) -2x1 : H surface is due to inelastic electronic excitation of bonding-to-antibonding states of Si-H bond.
2) On Si(111)7x7surface, LEEs with energies higher than 7.5 eV induce the bond rupture at adatom sites on the topmost layer of the reconstructed surface. The bond rupture efficiency has been measured as a function of the energy E_av, the maximum energy available for inelastic excitation. The efficiency shows the maximum at E_<av>=12eV, and decreases rapidly when the energy moves away from the energy. The morphological features of LEE-induced vacancies at adatom sites are the same as those for the laser-excitation. The available energy giving the maximum efficiency coincides with the plasma excitation energy of Si crystal. The obtained results provide the first evidence for the bond rupture on semiconductor surfaces induced by plasmon excitation.
3) Bond rupture on the InP (110) 1x1 surfaces is induced by holes injected from a STM tip, not by electrons, providing a direct proof that hole is the excited species responsible for the electronic bond rupture on semiconductors. The efficiency is quadratic with respect to the tunneling current. The obtained results suggest strongly that localization of two holes injected to the surface plays important roles in the bond rupture, similarly to the case of laser-induced bond rupture on semiconductor surfaces.
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Research Products
(89 results)
