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

Ran Jiang¹, Zuyin Han¹, Weideng Sun¹, Xianghao Du¹, Zhengran Wu¹ and Hyung-Suk Jung²
http://scitation.aip.org/content/aip/journal/apl/107/15/10.1063/1.4933275
1 Physical School, Shandong University, 27# Shanda Southern Road, Jinan, Shandong 250100, China
2 Department of Materials Science and Engineering, Seoul National University, Seoul 151-747, South Korea
Appl. Phys. Lett. 107, 151105 (2015); http://dx.doi.org/10.1063/1.4933275

Ferroelectric-field-effect-tunable modulation of terahertz waves in graphene/Si:HfO2/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:HfO2 layer. Considering the good compatibility of HfO2 on Si-basedsemiconductor process, the ferroelectricity layer of Si:HfO2 may open up an avenue for the tunable modulation of Thz wave.