  We report the structural, magnetic and electronic transport properties of
SrFe$_{2-x}$Cu$_x$As$_2$ single crystals grown by self-flux technique.
SrCu$_2$As$_2$ and SrFe$_2$As$_2$ both crystallize in ThCr$_2$Si$_2$-type
(122-type) structure at room temperature, but exhibit distinct magnetic and
electronic transport properties. The x-ray photoelectron spectroscopy(XPS)
Cu-2p core line position, resistivity, susceptibility and positive Hall
coefficient indicate that SrCu$_2$As$_2$ is an sp-band metal with Cu in the
3d$^{10}$ electronic configuration corresponding to the valence state
Cu$^{1+}$. The almost unchanged Cu-2p core line position in
SrFe$_{2-x}$Cu$_x$As$_2$ compared with SrCu$_2$As$_2$ indicates that partial Cu
substitutions for Fe in SrFe$_2$As$_2$ may result in hole doping rather than
the expected electron doping. No superconductivity is induced by Cu
substitution on Fe sites, even though the structural/spin density wave(SDW)
transition is gradually suppressed with increasing Cu doping.
