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Fortune, Torben Ray

Publications and source records attributed to Fortune, Torben Ray.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Monolithically-Fabricated Tunable Long-Wave Infrared Detectors Based on Dynamic Graphene Metasurfaces.

In this paper, the design, fabrication, and characterization of an actively tunable long-wave infrared detector, made possible through direct integration of a graphene-enabled metasurface with a conventional type-II superlattice infrared detector, are reported. This structure allows for post-fabrication tuning of the detector spectral response through voltage-induced modification of the carrier density within graphene and, therefore, its plasmonic response. These changes modify the transmittance through the metasurface, which is fabricated monolithically atop the detector, allowing for spectral control of light reaching the detector. Importantly, this structure provides a fabrication-controlled alignment of the metasurface filter to the detector pixel and is entirely solid-state. Using single pixel devices, relative changes in the spectral response exceeding 8% have been realized. These proof-of-concept devices present a path toward solid-state hyperspectral imaging with independent pixel-to-pixel spectral control through a voltage-actuated dynamic response.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

Superlattice photodetector having improved carrier mobility

In a superlattice (SL) photodetector, each period of the SL includes first and second semiconductor layers having different compositions, at least one of which comprises indium arsenide (InAs). At least one of these two semiconductor layers has a graded composition. In embodiments, the first semiconductor layer comprises InAs and the second semiconductor layer is a graded layer comprising indium arsenide antimonide (InAsSb), wherein the antimony (Sb) concentration is varied. In examples, the Sb concentration in the second layer gradually increases from the top and bottom toward the middle of the layer.

Kim, Jin K.↗