Abstract
Doped hydrogenated amorphous silicon
(
a
-Si
:
H
)
films of only a few nanometer thin find application in
a
-Si
:
H
/crystalline silicon heterojunction solar cells. Although such films may yield a field effect at the interface, their electronic passivation properties are often found to be inferior, compared to those of their intrinsic counterparts. In this article, based on
H
2
effusion experiments, the authors argue that this phenomenon is caused by Fermi energy dependent Si-H bond rupture in the
a
-Si
:
H
films, for either type of doping. This results in the creation of Si dangling bonds, counteracting intentional doping of the
a
-Si
:
H
matrix, and lowering the passivation quality.