  As a potential solution for low-cost efficient solar cells, radial junctions
consisting of ZnO nanowires arrays embedded in Cu2O thin films have been
theoretically modeled. Calculations have been performed to explore the
geometric dependence of performance of such wire-based solar cells. By properly
setting material properties and cell dimensions, a reasonable power conversion
efficiency of 19.7% can be expected in a material with 2 {\mu}m minority
carrier diffusion length. The detrimental effects of bulk, interface and
contact-related states on solar cell performance have also been studied, from
which the efficiencies between ~22% and ~12% for a series of materials, ranging
from optimal to seriously poor-quality, are extracted. The findings suggest
that rational device design plays a crucial role in implementing efficient
Cu2O/ZnO wire radial junction solar cells.
