  Transverse momentum ($p_\mathrm{T}$) distribution of electrons for
$0.3<p_\mathrm{T}<9.0$ GeV/$c$ have been measured in midrapidity
($|\eta|<0.35$) in Au + Au collisions and $p$ + $p$ collisions at
$\sqrt{s_{NN}} = 200$ GeV by the RHIC-PHENIX experiment. Two methods for
background subtraction were applied to determine the electron yield from open
charm and bottom decays. The nuclear modification factor was calculated, and
significant suppression at high-$p_\mathrm{T}$ was observed in Au + Au
collisions, indicating substantial energy loss of heavy quarks in the dense
medium.
