Confinement effects in crystallization and Er doping of Si nanostructures

✍ Scribed by M. Zacharias; J. Heitmann; M. Schmidt; P. Streitenberger

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 181 KB
• Volume: 11
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/s1386-9477(01)00212-0

✦ Synopsis

This article presents our comprehensive investigation of the crystallization of amorphous silicon ÿlms with a layer thickness below 20 nm from an experimental as well as from a theoretical point of view. The exponential scaling of the crystallization temperature with layer thickness is derived by using solid state crystallization theory. The critical height of the nanocrystals embedded in such superlattice structures depends on the speciÿc interface free energies of the respective phases (oxide, amorphous Si, and crystalline Si) and exponentially on the layer thickness. In addition, strong enhancement of room temperature luminescence from Er ions embedded in the vicinity of Si nanocrystals is shown. Spatially resolved photoluminescence investigations and Rutherford backscattering measurements for Si and Er distributions along the same line scan clearly manifest that inhomogeneities in implantation are not the cause of the correlated increase of Er and decrease of nc-Si luminescence. However, this e ect can be understood as a coupling of radiative processes, which includes an energy transfer from Si nanocrystals to Er ions.