  To clarify the ultrafast temporal interplay of the different photocurrent
mechanisms occurring in single InAs-nanowire-based circuits, an on-chip
photocurrent pump-probe spectroscopy based on coplanar striplines was utilized.
The data are interpreted in terms of a photo-thermoelectric current and the
transport of photogenerated holes to the electrodes as the dominating ultrafast
photocurrent contributions. Moreover, it is shown that THz radiation is
generated in the optically excited InAs-nanowires, which is interpreted in
terms of a dominating photo-Dember effect. The results are relevant for
nanowire-based optoelectronic and photovoltaic applications as well as for the
design of nanowire-based THz sources.
