Semiconductor nanowires improve the performance of energy conversion devices

The next generation of semiconductor-based devices, such as photodetectors, solar cells and light-emitting diodes, could be made from nanowires instead of bulk thin films. Nanowires can be grown on a silicon surface, which is cheaper than the semiconducting surface required for bulk thin films. And various features of nanowires enable devices with improved performance and efficiency.

New work from LaPierre et al. describes how III-V nanowires can be used in energy conversion applications such as photovoltaics, thermoelectrics and betavoltaics. The nanowires can help increase the efficiency of silicon flat panel solar cells due to their absorption properties, while the diffuse scattering and backscattering of phonons inside nanowires can help make more efficient thermoelectric materials. As for betavoltaic applications, the geometrical shape of nanowires allow them to surround a radioactive material with a large surface area for capturing beta particles and boost the power output of the device. Nanowires with large bandgaps may also improve the conversion efficiency in betavoltaic devices.

Currently, the main challenge in building nanowire devices is controlling the growth and composition of the nanowires. Because the size, shape and spacing of nanowires on a surface is important and varies depending on the application, further materials and device development is needed before these applications can be realized.

Source: “Nanowires for energy: A review,” by N. I. Goktas, P. Wilson, A. Ghukasyan, D. Wagner, S. McNamee, and R. R. LaPierre, Applied Physics Reviews (2018). The article can be accessed at https://doi.org/10.1063/1.5054842 .