The Role of Valley Degeneracy in Carrier Extraction in Valley Photovoltaic Solar Cells

By operating a hot carrier solar cell optically at the absorber yet electronically at upper valleys of the band structure, a path to surpassing the single gap efficiency limit becomes viable. In pursuit of this, a set of InGaAs heterostructures have been produced in search of an effective extraction pathway for both high energy ‘hot’ carriers and low energy carriers accelerated to the upper valleys by the internal electric field. The requirements of band alignments, intervalley scattering, and electric field strength guide an approach toward a practical valley photovoltaic hot carrier solar cell.