Photodetectors

Towards single photon sensing

The figures below show how bandgaps can be tuned with lattice constant in III-V and II-VI alloys. Clearly going down the column of a periodic table makes the lattice constant go up and the bandgap go down. Our focus is on building a detailed model of the underlying materials chemistry of optoelectronic materials, understand the impact on band-alignment and build transport models that connect them with optoelectronic properties, such as detectivity in Mid-IR photodiodes, or gain-bandwidth product in III-V avalanche photodetectors.

 

 

The figure below shows how different slices of the IR spectrum can be accessible with different alloy combinations.

  • Pb salt based MWIR PDs

    Pb salt based MWIR PDs

     

     

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  • HCT PDs

    HCT PDs

    Mercury Cadmium Telluride (Hg1-xCdxTe) or HCT has opened up versatile opportunities for photodetector designing within the whole range of Infrared (IR) wavelength due to its bandgap tunability with different Cd mole fraction, x. Our work is focused on MWIR HCT photodetectors.

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  • III-V APDs

    III-V APDs

    III-V digital alloy avalanche photodiodes are highly suitable for LIDAR system and telecommunications applications due to their low excess noise and high gain-bandwidth product. These short-period superlattices have broad bandgap tunability and offer unique material properties. We focus on understanding and modeling these properties.

     

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