Photodetectors are important part for photonic circuitry, which converts photons to electric signal. The ability of a photonic device to convert light energy to electrical energy depends on the band gap of the photoconductive material, which dictates how efficiently the material can absorb depending on the frequency of the light energy. Existing photoconductive materials are inefficient at absorbing light energy and converting that light energy to an electrical signal because they have a large band gap—generally between 1 and 3 electronvolts (eV). Therefore, there is a need for photonic devices with a material that can absorb light more efficiently.
Researchers at GW have developed a photodetector with high responsivity of 0.01 A/W (Amps to Watts) and ˜0.5 A/W at 1550 nm. The photonic device includes two electrodes and a two-dimensional (2D) material electrically connecting the two electrodes. The 2D material is made up of Molybdenum ditelluride (MoTe2). Strain is induced in the 2D material to reduce the band gap and increase the efficiency of the photodetector. The device responsivity can be further improved using a high-Q cavity resonator.
Figure 1. Microring resonator integrated photodetector
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