The Boeing Company

Peter C Colter

Richard Roland King

Christopher M Fetzer

James H Ermer

Nasser H Karam

Moran Haddad

Chris Fetzer

A solar cell includes a first layer having a first-layer lattice parameter, a second layer having a second-layer lattice parameter different from the first-layer lattice parameter, wherein the second layer includes a photoactive second-layer material; and a third layer having a third-layer lattice parameter different from the second-layer lattice parameter, wherein the third layer includes a photoactive third-layer material. A transparent buffer layer extends between and contacts the second layer and the third layer and has a buffer-layer lattice parameter that varies with increasing distance from the second layer toward the third layer, so as to lattice match to the second layer and to the third layer. There may be additional subcell layers and buffer layers in the solar cell.

Solar cells having a transparent composition-graded buffer layer

A method of disordering a layer of an optoelectronic device including; growing a plurality of lower layers; introducing an isoelectronic surfactant; growing a layer; allowing the surfactant to desorb; and growing subsequent layers all performed at a low pressure of 25 torr.

Isoelectronic surfactant induced sublattice disordering in optoelectronic devices

The present invention provides a photovoltaic cell comprising a GaInP subcell comprising a disordered group-III sublattice, a Ga(In)As subcell disposed below the GaInP subcell, and a Ge substrate disposed below the Ga(In)As subcell comprising a surface misoriented from a (100) plane by an angle from about 8 degrees to about 40 degrees toward a nearest (111) plane.

Multijunction photovoltaic cell grown on high-miscut-angle substrate

A multijunction solar cell includes a first photoactive subcell layer having a first-subcell lattice parameter and a composition including (a) at least one Group III element, at least one Group V element other than (nitrogen, phosphorus), and (nitrogen, phosphorus), or (b) a material selected from the group including GaInAsBi, GaInAsSb, GaInAsP, ZnGeAs, or BGaInAs. The multijunction solar cell also has a substrate having a substrate lattice parameter different from the first-subcell lattice parameter, and a composition-graded buffer layer between the first photoactive subcell layer and the substrate and having a buffer-layer lattice parameter graded between the first-subcell lattice parameter and the substrate lattice parameter. The substrate may be a second photoactive subcell layer having a second-subcell lattice parameter different from the first-subcell lattice parameter and sensitive to a second-photoactive-subcell-layer wavelength, and the buffer layer is transparent to the second-photoactive-subcell-layer wavelength.

Multijunction solar cell having a lattice mismatched GrIII-GrV-X layer and a composition-graded buffer layer

A photovoltaic cell or other optoelectronic device having a wide-bandgap semiconductor used in the window layer. This wider bandgap is achieved by using a semiconductor composition that is not lattice-matched to the cell layer directly beneath it and/or to the growth substrate. The wider bandgap of the window layer increases the transmission of short wavelength light into the emitter and base layers of the photovoltaic cell. This in turn increases the current generation in the photovoltaic cell. Additionally, the wider bandgap of the lattice mismatched window layer inhibits minority carrier injection and recombination in the window layer.

Wide-bandgap, lattice-mismatched window layer for a solar conversion device

A perfectly or approximately lattice-matched semiconductor layer for use in an electronic or optoelectronic device. Perfectly lattice-matched (&ldquo;PLM&rdquo;) semiconductor layers prevent or lessen the formation and propagation of crystal defects in semiconductor devices, defects that can decrease the performance characteristics of the device. For some semiconductors, the ability to optimize composition-dependent properties over the wider range of compositions that approximately lattice-matched (&ldquo;ALM&rdquo;) semiconductor layers allows is more advantageous than the lower strain and dislocation density encountered for PLM layers. In addition, PLM cell layers and ALM cell layers are also expected to result in improved radiation resistance characteristics for some semiconductor devices.

Growing community of inventors

Canyon Country, CA, United States of America

Peter C Colter