Tunable Hot-Carrier Spectral Photodetector

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Introduction: The detection of infrared radiation is important in a wide range of applications in the civilian, industrial, medical, astronomical, and military sectors. The spectral response of common optoelectronic photodetectors is confined to specific wavelength ranges in accordance with their bandgaps. This spectral rule dominates device design and intrinsically limits the wavelength ranges that can be detected, and existing design methods have been unable to overcome this detection limit without a problematic alteration of other parameters like detector noise and maximum operating temperature. Therefore, there is a need for improved mechanisms for photodetection that can overcome these wavelength detection limits without unwanted that can tune the wavelength to varying limits while avoiding the negative effects on other important device parameters. Technology: Georgia State University researchers have invented a high-performance spectral detector that overcomes the spectral limit by utilizing a hot-cold hole energy transfer mechanism � hot carriers injected into a semiconductor structure interact with cold carriers and excite them to higher energy states. This results in a very long-wavelength infrared response. With the additional degree of freedom enabled by tuning the energies of cold carriers, it is possible for a particular material to respond above its typical spectral limit. The proposed tunable photodetector enables individual optimization of the maximum wavelength limit and the activation energy to achieve targeted wavelengths for detection while simultaneously minimizing the detector noise and dark current.