Transparent, low-resistive
contacts are critical for efficient solar energy harvesting devices.
It is important to reconsider the material choices and electrode design
as devices move from 2D films to 1D nanostructures. In this paper,
we study the effectiveness of indium tin oxide (ITO) and metals, such
as Ag and Cu, as contacts in 2D and 1D systems. Although ITO has been
studied extensively and developed into an effective transparent contact
for 2D devices, our results show that effectiveness does not translate
to 1D systems. Particularly with consideration of resistance requirement,
nanowires with metal shells as contacts enable better absorption within
the semiconductor as compared to ITO. Furthermore, there is a strong
dependence of contact performance on the semiconductor band gap and
diameter of nanowires. We found that metal contacts outperform ITO
for nanowire devices, regardless of the sheet resistance constraint,
in the regime of diameters less than 100 nm and band-gaps greater
than 1 eV. These metal shells optimized for best absorption are significantly
thinner than ITO, which enables for the design of devices with high
nanowire number density and consequently higher device efficiencies
