Transition metal impurities have a large atomic radius and are readily
voids or multivacancies.
Indeed, there have been several studies of the gettering effect of voids
Within the void, there is a possibility of a molecular hydride species being
for example, AuH, AgH, PtH2 and PdH2. The molecular species are known
to be thermally stable, e.g.
AuH has a
dissociation energy of 3.1 eV. To investigate their properties within Si,
calculations were carried out on clusters containing
a decavacancy whose surface is saturated with H.
The ionisation energies and electron
affinities of TMH hydrides inserted into this microvoid
these defects possess no gap levels and as such represent a means
by which the impurity is passivated. However, whereas it is known that voids
in plasma treated or H-implanted material, it is unclear whether they, or
multivacancy centres, can be