中国物理B ›› 2007, Vol. 16 ›› Issue (9): 2661-2664.doi: 10.1088/1009-1963/16/9/028

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Formation and local electronic structure of Ge clusters on Si(111)-7×7 surfaces

马海峰, 徐明春, 杨冰, 时东霞, 郭海明, 庞世瑾, 高鸿钧   

  1. Nanoscale Physics and Devices Laboratory, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
  • 收稿日期:2007-01-24 修回日期:2007-04-04 出版日期:2007-09-20 发布日期:2007-09-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos~90406022 and 10674159).

Formation and local electronic structure of Ge clusters on Si(111)-7×7 surfaces

Ma Hai-Feng(马海峰), Xu Ming-Chun(徐明春), Yang Bing(杨冰), Shi Dong-Xia(时东霞), Guo Hai-Ming(郭海明), Pang Shi-Jin(庞世瑾), and Gao Hong-Jun(高鸿钧)†   

  1. Nanoscale Physics and Devices Laboratory, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
  • Received:2007-01-24 Revised:2007-04-04 Online:2007-09-20 Published:2007-09-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos~90406022 and 10674159).

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摘要： We report the formation and local electronic structure of Ge clusters on the Si(111)-7$\times $7 surface studied by using variable temperature scanning tunnelling microscopy (VT-STM) and low-temperature scanning tunnelling spectroscopy (STS). Atom-resolved STM images reveal that the Ge atoms are prone to forming clusters with 1.0~nm in diameter for coverage up to 0.12~ML. Such Ge clusters preferentially nucleate at the centre of the faulted-half unit cells, leading to the `dark sites' of Si centre adatoms from the surrounding three unfaulted-half unit cells in filled-state images. Bias-dependent STM images show the charge transfer from the neighbouring Si adatoms to Ge clusters. Low-temperature STS of the Ge clusters reveals that there is a band gap on the Ge cluster and the large voltage threshold is about 0.9~V.

关键词: scanning tunnelling microscopy, Si(111)-7\times 7 surface, Ge cluster

Abstract: We report the formation and local electronic structure of Ge clusters on the Si(111)-7$\times $7 surface studied by using variable temperature scanning tunnelling microscopy (VT-STM) and low-temperature scanning tunnelling spectroscopy (STS). Atom-resolved STM images reveal that the Ge atoms are prone to forming clusters with 1.0 nm in diameter for coverage up to 0.12 ML. Such Ge clusters preferentially nucleate at the centre of the faulted-half unit cells, leading to the `dark sites' of Si centre adatoms from the surrounding three unfaulted-half unit cells in filled-state images. Bias-dependent STM images show the charge transfer from the neighbouring Si adatoms to Ge clusters. Low-temperature STS of the Ge clusters reveals that there is a band gap on the Ge cluster and the large voltage threshold is about 0.9 V.

Key words: scanning tunnelling microscopy, Si(111)-7$\times$ 7 surface, Ge cluster

中图分类号:  (Electronic structure of nanoscale materials and related systems)

  • 73.22.-f
68.37.Ef (Scanning tunneling microscopy (including chemistry induced with STM)) 68.47.Fg (Semiconductor surfaces) 73.20.At (Surface states, band structure, electron density of states)