  As the first intrinsic antiferromagnetic topological insulator,
MnBi$_2$Te$_4$ has provided a platform to investigate the interplay of band
topology and magnetism as well as the emergent phenomena arising from such an
interplay. Here we report the chemical-vapor-transport (CVT) growth and
characterization of MnBi$_2$Te$_4$, as well as the observation of the
field-induced quantized Hall conductance in 6-layer devices. Through
comparative studies between our CVT-grown and flux-grown MnBi$_2$Te$_4$ via
magnetic, transport, scanning tunneling microscopy, and angle-resolved
photoemission spectroscopy measurements, we find that CVT-grown MnBi$_2$Te$_4$
is marked with higher Mn occupancy on the Mn site, slightly higher
Mn$_{\rm{Bi}}$ antisites, smaller carrier concentration and a Fermi level
closer to the Dirac point. Furthermore, a 6-layer device made from the
CVT-grown sample shows by far the highest mobility of 2500 cm$^2$V$\cdot$s in
MnBi$_2$Te$_4$ devices with the quantized Hall conductance appearing at 1.8 K
and 8 T. Our study provides a new route to obtain high-quality single crystals
of MnBi$_2$Te$_4$ that are promising to make superior devices and realize
emergent phenomena, such as the layer Hall effect and quantized anomalous hall
effect, etc.
