Their measurement technique, known as optical pump–terahertz probe (OPTP) spectroscopy, is ideally suited to nanowires: it allows non-contact measurements of carrier transport and dynamics at room temperature with sub-picosecond resolution. The Oxford team used OPTP spectroscopy to study and contrast the crucial electronic properties of GaAs, InAs and InP nanowires.

Guiding device design and future research

As the team explains, OPTP measurements will guide the choice of nanowires for different applications, and identify future challenges in improving nanowire properties. For example, InP nanowires exhibited remarkably long photoconductivity lifetimes of over 1 ns and an extremely low surface recombination velocity. This suggests that InP nanowires are excellent candidates for devices such as solar cells in which charge collection efficiency is critical. In contrast the short (2 ps) carrier lifetimes in GaAs nanowires indicates suitability for high-speed devices. Finally, InAs nanowires exhibited the highest electron mobilities of 6000 cm2V–1s–1, which highlights their potential in future high-mobility devices such as field effect transistors.

Additional information can be found in the journal Nanotechnology.