Tuesday, October 13, 2015

Abstract-Ferroelectric modulation of terahertz waves with graphene/ultrathin-Si:HfO2/Si structures

Ferroelectric-field-effect-tunable modulation of terahertz waves in graphene/Si:HfO/Si stack structure was observed. The modulation shows distinct behaviors when the samples under different gate polarities. At a negative voltage, a transmission modulation depth up to ∼74% was present without depending on the photo illumination power, whereas, at a positive voltage, the modulation of Thz wave shows dependence on the illumination power, which is ascribed to the creation/elimination of an extra barrier in Si layer in response to the polarization in the ferroelectric Si:HfO layer. Considering the good compatibility of HfO on Si-basedsemiconductor process, the ferroelectricity layer of Si:HfO may open up an avenue for the tunable modulation of Thz wave.

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