Bulletin of Materials Science

, Volume 22, Issue 3, pp 377–381

Optical properties of tetragonal germanium nanocrystals deposited by the cluster-beam evaporation technique: New light emitting material for future

  • S Nozaki
  • S Sato
  • S Rath
  • H Ono
  • H Morisaki
Semiconductors, Photovoltaics And Optoelectronic Materials

DOI: 10.1007/BF02749945

Cite this article as:
Nozaki, S., Sato, S., Rath, S. et al. Bull Mater Sci (1999) 22: 377. doi:10.1007/BF02749945

Abstract

The germanium (Ge) nanocrystals were deposited on substrates whose temperature was kept at room or liquid nitrogen (LN2) temperature by the cluster-beam evaporation technique. The deposited films are found to consist of the tetragonal crystalline structure rather than the diamond structure of bulk Ge. Such a phase-transition has been theoretically predicted for sizes smaller than 4 nm, which agrees with the size measured by the transmission electron microscopy (TEM). The tetragonal Ge is expected to have a direct band gap of 1·47 eV. Furthermore, the Ge film deposited at LN2 temperature exhibits unique properties, such as photo-oxidation and blue-light emission. The Ge-nanocrystal films deposited by the cluster-beam evaporation technique are attractive materials for application to light emitting devices in future.

Keywords

Germaniumnanocrystalcrystal structureST-12photo-oxidationblue-light emission

Copyright information

© Indian Academy of Sciences 1999

Authors and Affiliations

  • S Nozaki
    • 1
  • S Sato
    • 1
  • S Rath
    • 1
  • H Ono
    • 1
  • H Morisaki
    • 1
  1. 1.Department of Communications and SystemsThe University of Electro-CommunicationsChofu-shi, TokyoJapan