Ultrafast photocurrents and THz generation in single InAs-nanowires

To clarify the ultrafast temporal interplay of the different photocurrent mechanisms occurring in single InAsnanowire- based circuits, an on-chip photocurrent pumpprobe spectroscopy based on coplanar striplines was utilized. The data are interpreted in terms of a photothermoelectric 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 InAsnanowires, which is interpreted in terms of a dominating photo-Dember effect. The results are relevant for nanowirebased optoelectronic and photovoltaic applications as well as for the design of nanowire-based THz sources.