Modeling of negatively charged states at the Ge surface and interfaces
P Tsipas, A Dimoulas - Applied Physics Letters, 2009 - pubs.aip.org
Modeling based on surface charge neutrality predicts that the Ge surface tends to be p-type,
irrespective of the bulk conductivity. This is a consequence of the fact that the Ge band gap
is small and the charge neutrality level lies low in the gap very close to the valence band,
probably determined by low-lying unpassivated surface dangling bond acceptors or other
defects. According to the model, the acceptor defects build negative charge, inverting the
surface of n-type Ge at no gate bias for low doping concentration (< 10 16 cm− 3) and …
irrespective of the bulk conductivity. This is a consequence of the fact that the Ge band gap
is small and the charge neutrality level lies low in the gap very close to the valence band,
probably determined by low-lying unpassivated surface dangling bond acceptors or other
defects. According to the model, the acceptor defects build negative charge, inverting the
surface of n-type Ge at no gate bias for low doping concentration (< 10 16 cm− 3) and …