Nanoscale semiconductor materials, such as III–V nanowires, offer unique properties and routes towards novel device concepts. Examples of such devices include nanowire-based terahertz-band polarisation-modulators and optical memory devices. The nanoscale size of these structures, from which stems their remarkable properties, however poses challenges for their characterisation and integration into devices. Higher-throughput and scalable approaches are needed to address these challenges.

Contact-free electrical measurements, such as terahertz conductivity spectroscopy, circumvent the problems associated with conventional electrode-based measurements. Optical pump–terahertz probe (OPTP) spectroscopy - a variant of terahertz conductivity spectroscopy - is capable of measuring charge carrier mobilities, charge carrier lifetimes (with sub-picosecond temporal resolution), ionised dopant concentrations and surface recombination velocities, in a completely contact-free manner. For example, recently, OPTP spectroscopy revealed the effectiveness of ultrathin InP shells on improving the charge carrier lifetimes of InAsP nanowire cores.

Another solution is the automation of device design and fabrication. Using automated microscopy and machine vision with lithographically compatible alignment markers, we have automated the process of identifying and locating individual nanowires within a randomly positioned distribution. This step is followed by an automated process of electrode design which allows the rapid fabrication of hundreds of single-nanowire devices. These automated methods also enable cross-correlation down to the single-nanowire level between complementary characterisation techniques such as field-effect measurements, photoluminescence spectroscopy and terahertz conductivity spectroscopy.