  Due to the unique three-dimensional (3-D) geometries of nanowire-i.e., large
surface-to-volume ratios and smaller cross-sections at the nanowire-substrate
interfaces-their carrier dynamics are much more complicated than those of thin
films. Therefore, analytical solutions cannot be found for these nanostructures
and a more comprehensive scheme of 3-D modeling is necessary to interpret their
intrinsic carrier dynamics. To date, most modeling studies for nanowires have
focused on electromagnetic properties (e.g. optical modes and optical
absorption). However, very few studies have combined optical and electrical
simulations together to probe the temporal and spatial carrier motions within
nanowires. In this work, we present a comprehensive nanowire optoelectronic
transient model and photoresponse model, allowing us to investigate carrier
lifetimes and their fundamental correlations with material properties, as well
as responsivities and detectivities for nanowire-based optical devices for
photodetection (i.e., photodetectors). We believe this work can stimulate
further experimental and theoretical work and unveil the real strength of 3-D
computational models for exploring carrier dynamics in nanowires and
nanostructured materials.
