Speaker
Description
Since MOS scaling, metallic interconnects causes limitations of data rate and ultrahigh power dissipation. Compared with electrical interconnects, optical interconnects allow higher operation speed and lower power consumption for high-bandwidth-density chip-to-chip interconnects. However, for important components of optoelectronic integration circuits (OEICs) photodetectors does not meet the requirement of the present ultrahigh density integration. The common dimension of one imaging CCD (charged-coupled device) pixel still sticks on the micrometre scale, which is far beyond the feature size of the most advanced field effect transistors. In addition, for scaling photodetectors into the nanometer scale, its capacitance must be minimized, enabling a faster operation speed. The main issue of scaling photodetectors lies in the resulting low responsivity below the diffraction limit, also referred to as the famous efficiency-speed trade-off. One of the possible solutions is utilizing the light concentrating properties of metallic nanostructures by adding a plasmonic antenna.
Here, we study CMOS-compatible Al-Ge-Al heterojunctions on GeOI wafer, enabling nanometre-scale Ge phototransistors in the back-gate FET configuration. Aluminum electrodes act as a natural plasmonic antenna, maintaining a high responsivity even in the nanometer scale. With the assistant of the back gate, the refractive index of the Ge channel can be modulated, thus leading to a tunable polarization ratio. We believe our research provides a potential nano-metre phototransistor for optoelectronic integration circuits.
| Speaker Country | Austria |
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