Fetzer, Christopher M.

DOE OSTI2019

Highly doped layer for tunnel junctions in solar cells

A highly doped layer for interconnecting tunnel junctions in multijunction solar cells is presented. The highly doped layer is a delta-doped layer in one or both layers of a tunnel diode junction used to connect two or more p-on-n or n-on-p solar cells in a multijunction solar cell. A delta-doped layer is made by interrupting the epitaxial growth of one of the layers of the tunnel diode, depositing a delta dopant at a concentration substantially greater than the concentration used in growing the layer of the tunnel diode, and then continuing to epitaxially grow the remaining tunnel diode.

Fetzer, Christopher M.↗

DOE OSTI2019

Metamorphic solar cell having improved current generation

A semiconductor device structure having increased photogenerated current density, and increased current output is disclosed. The device includes low bandgap absorber regions that increase the range of wavelengths at which photogeneration of charge carriers takes place, and for which useful current can be collected. The low bandgap absorber regions may be strain balanced by strain-compensation regions, and the low bandgap absorber regions and strain-compensation regions may be formed from the same ternary semiconductor family. The device may be a solar cell, subcell, or other optoelectronic device with a metamorphic or lattice-mismatched base layer, for which the low bandgap absorber region improves the effective bandgap combination of subcells and current balance within the multijunction cell, for higher efficiency conversion of the solar spectrum.

14 SOLAR ENERGY↗