High performance III-V quantum dot photodetectors for low SWaP infrared devices

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Infrared radiation covers a wide electromagnetic spectrum from 0.78 to 1000 um. According to Planck's law, all objects radiate a large portion of infrared radiation at reasonable temperatures, e.g. <6000 K (the surface temperature of the Sun). As a result, infrared photonic systems can be applied to many fields, such as free-space communication, remote sensing, surveillance, spectroscopy, and hazard detection. Many of these applications require both high performance and high operating temperature. The focus of this project is on achieving high performance III-V quantum dot infrared photodetectors for low size, weight, and power (SWaP) devices. High operating temperature (HOT) III-V photodetectors with high quantum efficiency are technically important because the use of mature III-V semiconductors can significantly reduce the fabrication and material cost. More importantly, HOT photodetectors reduce the cooling requirements so that infrared systems can be low SWaP. Despite tremendous progress made in the last two decades, the demand for SWaP infrared photodetectors (particularly for wavelengths >2 micron) becomes increasingly urgent and yet to be met due to intrinsic drawbacks of existing technologies. This work proposes to exploit III-V quantum dot infrared photodetectors for high performance HOT photodetectors. By utilizing new designs and quantum structures, it is possible to improve the quantum efficiency and reduce the dark current, which provide a means of approaching the fundamental detectivity limit. Given that quantum dots are insensitive to defects, the potential of combining silicon electronics and III-V infrared sensing technology also provide a unique opportunity towards mid-infrared Si photonics for sensing and free-space communication, which leverages the near-infrared Si photonics developed for optical integrated circuits and data communication.