Harnessing Hot Carriers in Semiconductor Nanowires

In recent years, semiconducting nanowires have emerged as a promising platform to study hot-carrier extraction. With its precise engineering of heterostructures at the nanometer scale, nanowire growth facilitates the design of various energy filters for carrier separation and control of optoelectronic properties, including increased hot-carrier temperatures and possibilities to spatially control absorption [1]. Single nanowire devices with epitaxially defined energy filters have been used to realize thermal-to-electric energy conversion close to Carnot efficiency [2], as well as proof-of-principle hot-carrier photovoltaic devices reaching open-circuit voltages above the Shockley–Queisser limit [3].<br/><br/>To further understand the mechanism of hot-carrier extraction, and optimize the photovoltaic performance, we are characterizing single nanowire devices with various techniques focused on spatial control of hot-carrier excitation, such as implementation of plasmonic elements, electron-beam induced current measurements, and scanning photocurrent microscopy [4-5]. I will review the potential of using nanowires as a system for hot-carrier extraction, and present our progress towards implementing this in single nanowire devices.<br/><br/><b>References</b><br/>[1] Fast, J.; Aeberhard, U.; Bremner, S. P.; Linke, H. Hot-Carrier Optoelectronic Devices Based on Semiconductor Nanowires. <i>Applied Physics Reviews</i> <b>2021</b>, <i>8</i> (2), 021309.<br/>[2] Josefsson, M.; Svilans, A.; Burke, A. M.; Hoffmann, E. A.; Fahlvik, S.; Thelander, C.; Leijnse, M.; Linke, H. A Quantum-Dot Heat Engine Operating Close to the Thermodynamic Efficiency Limits. <i>Nature Nanotechnology</i> <b>2018</b>, <i>13</i> (10), 920–924.<br/>[3] Limpert, S.; Burke, A.; Chen, I.-J.; Anttu, N.; Lehmann, S.; Fahlvik, S.; Bremner, S.; Conibeer, G.; Thelander, C.; Pistol, M.-E.; Linke, H. Single-Nanowire, Low-Bandgap Hot Carrier Solar Cells with Tunable Open-Circuit Voltage. <i>Nanotechnology</i> <b>2017</b>, <i>28</i> (43), 434001.<br/>[4] Chen, I.-J.; Limpert, S.; Metaferia, W.; Thelander, C.; Samuelson, L.; Capasso, F.; Burke, A. M.; Linke, H. Hot-Carrier Extraction in Nanowire-Nanoantenna Photovoltaic Devices. <i>Nano Lett.</i> <b>2020</b>, <i>20</i> (6), 4064–4072.<br/>[5] Fast, J.; Barrigon, E.; Kumar, M.; Chen, Y.; Samuelson, L.; Borgström, M.; Gustafsson, A.; Limpert, S.; Burke, A.; Linke, H. Hot-Carrier Separation in Heterostructure Nanowires Observed by Electron-Beam Induced Current. <i>Nanotechnology</i> <b>2020</b>, <i>31</i> (39), 394004.