  We measure current by counting single electrons tunneling through an InAs
nanowire quantum dot. The charge detector is realized by fabricating a quantum
point contact in close vicinity to the nanowire. The results based on electron
counting compare well to a direct measurements of the quantum dot current, when
taking the finite bandwidth of the detector into account. The ability to detect
single electrons also opens up possibilities for manipulating and detecting
individual spins in nanowire quantum dots.
