Larsen, A. Nylandsted2; Goubet, J. J.2; Mejlholm, P.2; Christensen, J. Sherman2; Fanciulli, M.2; Gunnlaugsson, H. P.2; Weyer, G.2; Petersen, Jon Wulff3; Resende, A.10; Kaukonen, M.10; Jones, R.10; Öberg, S.5; Briddon, P. R.6; Svensson, B. G.7; Lindström, J. L.11; Dannefaer, S.12
1 Department of Micro- and Nanotechnology, Technical University of Denmark2 Aarhus University3 Risø National Laboratory for Sustainable Energy, Technical University of Denmark4 University of Exeter5 Luleå University6 University of Newcastle upon Tyne7 KTH - Royal Institute of Technology8 Lund University9 University of Winnipeg10 University of Exeter11 Lund University12 University of Winnipeg
Si crystals (n-type, fz) with doping levels between 1.5x10(14) and 2x10(16)cm(-3) containing in addition similar to 10(18) Sn/cm(3) were irradiated with 2-MeV electrons to different doses and subsequently studied by deep level transient spectroscopy, Mossbauer spectroscopy, and positron annihilation. Two tin-vacancy (Sn-V) levels at E-c - 0.214 eV and E-c - 0.501 eV have been identified (E-c denotes the conduction band edge). Based on investigations of the temperature dependence of the electron-capture cross sections, the electric-field dependence of the electron emissivity, the anneal temperature, and the defect-introduction rate, it is concluded that these levels are the double and single acceptor levels, respectively, of the Sn-V pair. These conclusions are in agreement with electronic structure calculations carried out using a local spin-density functional theory, incorporating pseudopotentials to eliminate the core electrons, and applied to large H-terminated clusters. Thus, the Sn-V pair in Si has five different charge states corresponding to four levels in the band gap.
Physical Review B (condensed Matter and Materials Physics), 2000, Vol 62, Issue 7, p. 4535-4544