  A series of tetragonal Fe$_{1-x}$Co${_x}$Se single crystals with a complete
Co doping range (0$\leq$x$\leq$0.52) up to its solid solubility limit in FeSe
have been grown by an eutectic AlCl${_3}$/KCl molten salt method. The typical
lateral size of as-grown Fe$_{1-x}$Co${_x}$Se single crystals is 1$-$5 mm. The
chemical composition and homogeneity of the crystals was examined by both
inductively coupled plasma atomic emission spectroscopy and energy dispersive
spectrometer. X-ray diffraction analysis demonstrates that the crystal lattice
parameters $a$ and $c$ are both linearly decreased with increasing Co doping
level x. In the whole doping range, all the samples show metallic behaviour in
contrast to a metal insulator transition of Cu-doped FeSe according to the
resistivity measurements
