We present a detailed picture of the electronic structure of donor-vacancy complexes in Ge-doped silicon and Si-doped germanium Clusters to mimic Si-rich and Ge-rich SiGe alloys, respectively Jahn-Teller effects and electrical levels were investigated in both Si-rich and Ge-rich end compositions It is shown that while Ge atoms act as efficient traps for mobile E-centers in Si-rich alloys, Si atoms in Ge-rich material do not have this ability A detailed linear combination of atomic orbitals model is proposed for VP-Ge and VP-Si complexes in Si1-xGex and Ge1-xSix, where the orbital filling order is driven by the larger electron affinity of Si atoms when compared to Ge. (C) 2009 Elsevier B.V. All rights reserved
Harald Brune, Stefano Rusponi, Marina Pivetta, Fabio Donati, Aparajita Singha