Quantum dot (QD) superlattices (SLs) have been proposed for improving solar cell efficiency by providing intermediate energy bands to allow sub-bandgap photon absorption , and to enhance the photocurrent in tandem solar cells . Although photocurrent enhancement from QD-based solar cells has been demonstrated , QD cells usually exhibit lower open-circuit voltages (V<SUB>OC</SUB>) and conversion efficiencies than the GaAs reference cells due to a bandgap reduction from the InAs QDs and their corresponding wetting layers (WLs). To avoid the limited QD density and the WL resulting from the misfit-driven Stranski-Krastanov QD growth process, we are pursuing an alternative approach, droplet epitaxy (DE). For DE of InAs QDs, nanoscale In droplets are deposited on GaAs and converted to InAs QDs via exposure to an As<SUB>2</SUB> flux. In this case, the QD size and density are determined primarily by the surface droplet size and density, which are not limited by the misfit between the QD and host matrix. Thus, DE provides a means to achieve ultra-high densities of ultra-small QDs, expected to enhance absorption and cell performance. For this purpose, we have investigated the influence of In exposure time on QD sizes and densities, revealing an increase in QD size homogeneity with decreasing In exposure. Specifically, for 2.5 ML equivalent of In deposition, a uniform distribution of QDs with an average diameter of ~20 nm is observed. To date, we have identified the appropriate In exposure time and substrate temperature to produce QD densities in excess of 3x10<SUP>10</SUP> cm<SUP>-2</SUP>. To further enhance the QD densities while maintaining a specific spatial arrangement of QDs, we are also exploring the influence of surface patterning on the formation of InAs/GaAs QDs by DE. For a buffer consisting of 2 ML equivalent of In deposited on GaAs at 100°C, a high density of mounds elongated along [-110] is apparent. These mounds are expected to enhance the QD densities due to preferential nucleation of QDs at the mound edges . The effects of GaAs droplet homoepitaxy nano-mound templates on the sizes, densities, and spatial arrangements of InAs QDs will be presented. In addition, we will discuss the influence of DE QD active regions on the photovoltaic properties of p-i-n structures.