| Dot-in-Well Quantum-Dot Infrared Photodetectors |
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| NASA’s Jet Propulsion Laboratory, Pasadena, California | |
| Feb 01 2008 | |
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advertisement: Heretofore, a typical QDIP has exhibited high dark current attributable partly to a high-band-gap ohmic contact layer and partly to the fact that because of the low density of QDs, the QDs do not occupy all of the cross section presented to incident light and, hence, some of the current flowing in the device does not pass through the detector material. The undesired effect of the high-band-gap contact layer can be overcome by adding a high-band-gap barrier layer or placing an undoped spacer layer of GaAs, between about 500 and 600 Å thick between the quantum wells and the top contact layer. It has been previously demonstrated that such spacer layers can significantly reduce tunneling injection currents from contacts to quantum-well regions, thereby reducing dark currents.
Recently, it has been discovered that QDIPs exhibit strong QWIP-like intersubband absorption. The practical significance of this discovery is that it should be possible to increase the coupling of light into QDIPs, thereby increasing quantum efficiencies, by use of two-dimensional gratings. This work was done by Sarath Gunapala, Sumith Bandara, David Ting, Cory Hill, John Liu, Jason Mumolo, and Yia Chung Chang of Caltech for NASA’s Jet Propulsion Laboratory. In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to: Innovative Technology Assets This Brief includes a Technical Support Package (TSP).
Dot-in-Well Quantum-Dot Infrared Photodetectors (reference NPO-42362) is currently available for download from the TSP library. Login first to download.
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