A method and device that incorporates metallic nanoparticles at the p+-n+
tunnel junction in a cascaded
photovoltaic solar cell. The use of the nanoparticles enhances the
tunneling current density through the
tunnel junction. As such, the efficiency of the
solar cell is increased. A method in accordance with the present invention comprises making a first
solar cell having a first bandgap, making a
tunnel junction coupled to the first
solar cell, and making a second solar
cell having a second bandgap, coupled to the tunnel junction opposite the first solar
cell, wherein the tunnel junction comprises nanoparticles. Such a method further optionally includes the nanoparticles being a
metal or a semi
metal, specifically a semi-
metal of
erbium arsenide, the nanoparticles being deposited in an island structure within the tunnel junction, and the first solar
cell being deposited on a flexible substrate. A device in accordance with the present invention comprises a tunnel junction, wherein the tunnel junction comprises nanoparticles between the n+ layer and the p+ layer of the tunnel junction. Such a device further optionally includes the device being a cascaded solar cell, the nanoparticles are a metal or semi-metal, specifically a semi-metal of
erbium arsenide, and the device is fabricated on a flexible substrate.