Ultrafast photocurrents and THz generation in single InAs-nanowires

TL;DR

This paper investigates ultrafast photocurrents and terahertz generation in single InAs nanowires using pump-probe spectroscopy, revealing dominant photo-thermoelectric and photo-Dember effects relevant for nanowire optoelectronics.

Contribution

It provides new insights into the ultrafast photocurrent mechanisms and THz generation in InAs nanowires, highlighting the roles of photo-thermoelectric and photo-Dember effects.

Findings

Photocurrents are dominated by photo-thermoelectric effects.

THz radiation is generated via the photo-Dember effect.

Ultrafast transport of photogenerated holes is observed.

Abstract

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.