First-principles study of the electronic properties of Ge dangling bonds at (100)Si1−xGex/SiO2 interfaces

Abstract

First-principles calculations of the electronic properties of (100)Si1−xGex/SiO2 structures, with a Ge dangling bond at the interface, are reported. It is found that the defect level associated with this dangling bond approaches the valence band edge of the Si1−xGex substrate as the Si concentration is reduced, mainly due to the narrowing of the energy bandgap of the alloy. These results suggest that these dangling bonds likely behave as acceptor-type defects at Ge-rich (100)Si1−xGex interfaces.