Abstract: According to one aspect, a hybrid heat transfer system includes a first thermally conductive path configured to passively transfer heat between a load having a load temperature (TL) and an ambient environment having an ambient temperature (TA), and a second thermally conductive path configured to actively transfer heat between the load and the ambient environment, the second path comprising a heat pump.

Abstract: Embodiments of a low resistivity ohmic contact are disclosed. In some embodiments, a method of fabricating a low resistivity ohmic contact includes providing a semiconductor material layer and intentionally roughening the semiconductor material layer to create a characteristic surface roughness. The method also includes providing an ohmic contact metal layer on a surface of the semiconductor material layer and providing a diffusion barrier metal layer on a surface of the ohmic contact metal layer opposite the semiconductor material layer. In this way, the adhesive force between the semiconductor material layer and the ohmic contact metal layer may be increased.

Abstract: Embodiments of a low resistivity ohmic contact are disclosed. In some embodiments, a method of fabricating a low resistivity ohmic contact includes providing a semiconductor material layer and intentionally roughening the semiconductor material layer to create a characteristic surface roughness. The method also includes providing an ohmic contact metal layer on a surface of the semiconductor material layer and providing a diffusion barrier metal layer on a surface of the ohmic contact metal layer opposite the semiconductor material layer. In this way, the adhesive force between the semiconductor material layer and the ohmic contact metal layer may be increased.

Abstract: Systems and methods for characterizing one or more properties of a material are disclosed. In some embodiments, the one or more properties include one or more thermal properties of the material, one or more thermoelectric properties of the material, and/or one or more thermomagnetic properties of the material. In some embodiments, a method of characterizing one or more properties of a sample material comprises heating the sample material and, while heating the sample material, obtaining one or more temperature measurements for at least one surface of the sample material via one or more thermoreflectance probes and obtaining one or more electric measurements for the sample material that correspond in time to the one or more temperature measurements. The method further comprises computing one or more parameters that characterize one or more properties of the sample material based on the measurements.

Abstract: A thermoelectric material and methods of manufacturing thereof are disclosed. In general, the thermoelectric material comprises a Group V-VI host, or matrix, material and Group III-V or Group IV-VI nanoinclusions within the Group V-VI host material. By incorporating the Group III-V or Group IV-VI nanoinclusions into the Group V-VI host material, the performance of the thermoelectric material can be improved.

Abstract: Embodiments of a thin-film heterostructure thermoelectric material and methods of fabrication thereof are disclosed. In general, the thermoelectric material is formed in a Group IIa and IV-VI materials system. The thermoelectric material includes an epitaxial heterostructure and exhibits high heat pumping and figure-of-merit performance in terms of Seebeck coefficient, electrical conductivity, and thermal conductivity over broad temperature ranges through appropriate engineering and judicious optimization of the epitaxial heterostructure.

Abstract: Embodiments of a low resistivity contact to a semiconductor structure are disclosed. In one embodiment, a semiconductor structure includes a semiconductor layer, a semiconductor contact layer having a low bandgap on a surface of the semiconductor layer, and an electrode on a surface of the semiconductor contact layer opposite the semiconductor layer. The bandgap of the semiconductor contact layer is in a range of and including 0 to 0.2 electron-volts (eV), more preferably in a range of and including 0 to 0.1 eV, even more preferably in a range of and including 0 to 0.05 eV. Preferably, the semiconductor layer is p-type. In one particular embodiment, the semiconductor contact layer and the electrode form an ohmic contact to the p-type semiconductor layer and, as a result of the low bandgap of the semiconductor contact layer, the ohmic contact has a resistivity that is less than 1×10?6 ohms·cm2.

Abstract: Embodiments of a thin-film heterostructure thermoelectric material and methods of fabrication thereof are disclosed. In general, the thermoelectric material is formed in a Group IIa and IV-VI materials system. The thermoelectric material includes an epitaxial heterostructure and exhibits high heat pumping and figure-of-merit performance in terms of Seebeck coefficient, electrical conductivity, and thermal conductivity over broad temperature ranges through appropriate engineering and judicious optimization of the epitaxial heterostructure.

Abstract: Embodiments of a low resistivity contact to a semiconductor structure are disclosed. In one embodiment, a semiconductor structure includes a semiconductor layer, a semiconductor contact layer having a low bandgap on a surface of the semiconductor layer, and an electrode on a surface of the semiconductor contact layer opposite the semiconductor layer. The bandgap of the semiconductor contact layer is in a range of and including 0 to 0.2 electron-volts (eV), more preferably in a range of and including 0 to 0.1 eV, even more preferably in a range of and including 0 to 0.05 eV. Preferably, the semiconductor layer is p-type. In one particular embodiment, the semiconductor contact layer and the electrode form an ohmic contact to the p-type semiconductor layer and, as a result of the low bandgap of the semiconductor contact layer, the ohmic contact has a resistivity that is less than 1×10?6 ohms·cm2.

Abstract: Embodiments of a thin-film heterostructure thermoelectric material and methods of fabrication thereof are disclosed. In general, the thermoelectric material is formed in a Group IIa and IV-VI materials system. The thermoelectric material includes an epitaxial heterostructure and exhibits high heat pumping and figure-of-merit performance in terms of Seebeck coefficient, electrical conductivity, and thermal conductivity over broad temperature ranges through appropriate engineering and judicious optimization of the epitaxial heterostructure.

Abstract: Embodiments of a thin-film heterostructure thermoelectric material and methods of fabrication thereof are disclosed. In general, the thermoelectric material is formed in a Group IIa and IV-VI materials system. The thermoelectric material includes an epitaxial heterostructure and exhibits high heat pumping and figure-of-merit performance in terms of Seebeck coefficient, electrical conductivity, and thermal conductivity over broad temperature ranges through appropriate engineering and judicious optimization of the epitaxial heterostructure.

Abstract: The present application is directed to a multi-terminal semiconductor solar cell. The solar cell may be dual junction solar cells comprising single junctions independently interconnected by a middle lateral conduction layer (MLCL). The solar cells may include a GaAs subcell, a GaInP subcell, and a MLCL disposed therebetween. In addition, the solar cells may include a plurality of terminals. One terminal may be operatively connected to the GaAs subcell, a second terminal may be operatively connected to the GaInP subcell and a third terminal may be operatively connected to the MLCL.

Abstract: A method of forming a multijunction solar cell including an upper subcell, a middle subcell, and a lower subcell, including: providing a substrate having an off-cut of 15° from the (001) plane to the (111)A plane for the epitaxial growth of semiconductor material; forming a first solar subcell on the substrate having a first band gap; forming a second solar subcell over the first solar subcell having a second band gap smaller than the first band gap; forming a grading interlayer over the second subcell layer, the grading interlayer having a third band gap greater than the second band gap; and forming a third solar subcell over the grading interlayer having a fourth band gap smaller than the second band gap such that the third subcell is lattice mismatched with respect to the second subcell.

Abstract: Symmetric quantum dots are embedded in quantum wells. The symmetry is achieved by using slightly off-axis substrates and/or overpressure during the quantum dot growth. The quantum dot structure can be used in a variety of applications, including semiconductor lasers.