Abstract: An optoelectronic device comprising: a first conductive layer, a second conductive layer, an active layer between the first conductive layer and the second conductive layer, wherein the active layer comprises a submicrometer size structure of hexagonal type crystals of an element or alloy of elements selected from the carbon group.

Abstract: A design of a quantum well region that allows faster and more efficient carrier collection in quantum well solar cells. It is shown that for a quantum well material system displaying a negligible valence band offset, the conduction band confinement energies and barrier thicknesses can be designed to favor a sequential thermionic promotion and resonant tunneling of electrons to the conduction band continuum resulting in faster carrier collection rates than for a conventional design. An evaluation of the proposed design in the context of devices incorporating GaAs/GaAsN quantum wells shows a collection of all photo-generated carriers within several to tenths of ps (10?12 s) from deep quantum wells rather than several ns, as it is the case for conventional designs. The incorporation of the proposed design in single and multijunction solar cells is evaluated with efficiency enhancements.

Abstract: A dilute nitrogen alloy of InNxSb1-x epilayers strained to an epitaxial substrate useful for Long Wavelength Infrared (LWIR) Focal Plane Arrays, and method of fabricating. Strained materials of composition InNxSb1-x exhibiting increased Auger lifetimes and improved absorption properties.

Abstract: A design of a quantum well region that allows faster and more efficient carrier collection in quantum well solar cells. It is shown that for a quantum well material system displaying a negligible valence band offset, the conduction band confinement energies and barrier thicknesses can be designed to favor a sequential thermionic promotion and resonant tunneling of electrons to the conduction band continuum resulting in faster carrier collection rates than for a conventional design. An evaluation of the proposed design in the context of devices incorporating GaAs/GaAsN quantum wells shows a collection of all photo-generated carriers within several to tenths of ps (10?12 s) from deep quantum wells rather than several ns, as it is the case for conventional designs. The incorporation of the proposed design in single and multijunction solar cells is evaluated with efficiency enhancements.

Abstract: An optoelectronic device comprising: a first conductive layer, a second conductive layer, an active layer between the first conductive layer and the second conductive layer, wherein the active layer comprises a submicrometer size structure of hexagonal type crystals of an element or alloy of elements selected from the carbon group.

Abstract: Multi-junction solar cell devices which incorporate dilute nitrides to include a sub-cell in the 1 eV range in a conventional design for a solar cell. Sub-cells may be inserted within the intrinsic region of a conventional GaAs p-i-n solar cell either as a 3rd junction (1 eV) in a (Al)InGaP (1.9 eV)/GaAs(1.42 eV)/MQW(1 eV)/Ge(0.66 eV) quadruple junction device or as a triple junction configuration with a 1.1 eV MQW between GaInP (1.8 eV) and Ge(0.66 eV).

Abstract: A dilute nitrogen alloy of InNxSb1-x epilayers strained to an epitaxial substrate useful for Long Wavelength Infrared (LWIR) Focal Plane Arrays, and method of fabricating. Strained materials of composition InNxSb1-x exhibiting increased Auger lifetimes and improved absorption properties.

Abstract: A two-terminal tandem solar cell is provided. The inclusion of thin (few nm-thick) narrow band-gap InGaAs quantum wells in the intrinsic (i) region of the conventional p-i-n GaAs solar cell extends the photo-absorption of the conventional GaInP/GaAs tandem cell toward the infrared. Beginning-of-Life efficiencies in excess of 30% are predicted. Modeling data indicate end-of-life efficiency of these cells will exceed 25% AM0.

Abstract: A two-terminal tandem solar cell is provided. The inclusion of thin (few nm-thick) narrow band-gap InGaAs quantum wells in the intrinsic (i) region of the conventional p-i-n GaAs solar cell extends the photo-absorption of the conventional GaInP/GaAs tandem cell toward the infrared. Beginning-of-Life efficiencies in excess of 30% are predicted. Modeling data indicate end-of-life efficiency of these cells will exceed 25% AM0.

Abstract: An indium phosphide photovoltaic cell is provided where one or more quantum wells are introduced between the conventional p-conductivity and n-conductivity indium phosphide layer. The approach allows the cell to convert the light over a wider range of wavelengths than a conventional single junction cell and in particular convert efficiently transparency losses of the indium phosphide conventional cell. The approach hence may be used to increase the cell current output.A method of fabrication of photovoltaic devices is provided where ternary InAsP and InGaAs alloys are used as well material in the quantum well region and results in an increase of the cell current output.

Abstract: A monolithic, tandem photovoltaic device is provided having an indium phosphide tunnel junction lattice-matched to adjoining subcells and having high peak current densities and low electrical resistance. A method is provided for relatively low-temperature epitaxial growth of a tunnel junction and a subcell over the tunnel junction at temperatures which leave intact the desirable characteristics of the tunnel junction.

Abstract: A monolithic, tandem photovoltaic device is provided having an indium gallium arsenide tunnel junction lattice-matched to adjoining subcells and having high peak current densities and low electrical resistance. A method is provided for relatively low-temperature epitaxial growth of a subcell over the tunnel junction at temperatures which leave intact the desirable characteristics of the tunnel junction.