  We report several quantum interference effects in graphene grown by chemical
vapor deposition. A crossover between weak localization and weak
antilocalization effects is observed when varying the gate voltage and we
discuss the underlying scattering mechanisms. The characteristic length scale
for phase coherence is compared with that estimated from universal conductance
fluctuations in the microporeformed graphene sample. These extensive
temperature- and gate-dependent measurements of the intervalley and intravalley
scattering lengths provide important and useful insight for the macroscopic
applications of graphene-based quantum devices.
