  We present low temperature transport measurements on double quantum dots in
InAs nanowires grown by metal-organic vapor phase epitaxy. Two dots in series
are created by lithographically defined top-gates with a procedure involving no
extra insulating layer. We demonstrate the full tunability from strong to weak
coupling between the dots. The quantum mechanical nature of the coupling leads
to the formation of a molecular state extending over both dots. The excitation
spectra of the individual dots are observable by their signatures in the
nonlinear transport.
