University of California

Cornell Research Foundation Inc.

Junqiao Wu

Wladyslaw Walukiewicz

Kin Man Yu

William J Schaff

Kechao Tang

A material platform with controllable emissivity and fabrication methods are provided that permit the manipulation of thermal radiation detection and IR signal modulation and can be adapted to a variety of uses including infrared camouflage, thermal IR decoys, thermo-reflectance imaging and IR signal modulation. The platform is a multilayer WVOfilm with different W doping levels (x values) and layer thicknesses, forming a graded W-doped construct. In WVOfilms with a total thickness <100 nm, the graded doping of W spreads the originally sharp metal-insulator phase transition (MIT) to a broad temperature range, greatly expanding the temperature window for emissivity modulation.

Flexible and tunable infrared emissivity material platform

The highly mismatched alloy ZnMnOTe, 0&#x2266;y&#x3c;1 and 0&#x3c;x&#x3c;1 and other Group II-IV-Oxygen implanted alloys have been synthesized using the combination of oxygen ion implantation and pulsed laser melting. Incorporation of small quantities of isovalent oxygen leads to the formation of a narrow, oxygen-derived band of extended states located within the band gap of the ZnMnTe host. With multiple band gaps that fall within the solar energy spectrum, ZnMnOTeis a material perfectly satisfying the conditions for single-junction photovoltaics with the potential for power conversion efficiencies surpassing 50%.

Multiband semiconductor compositions for photovoltaic devices

An alloy having a large band gap range is used in a multijunction solar cell to enhance utilization of the solar energy spectrum. In one embodiment, the alloy is InGaN having an energy bandgap range of approximately 0.7 eV to 3.4 eV, providing a good match to the solar energy spectrum. Multiple junctions having different bandgaps are stacked to form a solar cell. Each junction may have different bandgaps (realized by varying the alloy composition), and therefore be responsive to different parts of the spectrum. The junctions are stacked in such a manner that some bands of light pass through upper junctions to lower junctions that are responsive to such bands.

Growing community of inventors

Belmont, MA, United States of America

Junqiao Wu