  We report on the unexpected increase in the dephasing lengths of a graphene
sheet caused by the deposition of Pd nanoclusters, as demonstrated by weak
localization measurements. The dephasing lengths reached saturated values at
low temperatures. Theoretical calculations indicate the p-type charge transfer
from the Pd clusters, which contributes more carriers. The saturated values of
dephasing lengths often depend on both the carrier concentration and mean free
path. Although some impurities are increased as revealed by decreased
mobilities, the intense charge transfer leads to the improved saturated values
and subsequent improved dephasing lengths.
