Fig. 2: Fabrication and architecture of type-printable plasmonic photodetector.

a Schematic of the experimental setup for printing graphene/BiFeO₃ (BFO) superdomain-based plasmonic photodetector. The BFO film epitaxial growth on an SrTiO₃ (STO) substrate with a covering LSMO (La_xSr_1−xMnO₃) electrode layer. b Piezoelectric force microscopy (PFM) phase image of BFO superdomain, showing the periodical ribbons patterned adjacent to upward and downward domains. c G-band frequency mapping for graphene on BFO superdomain. The scale bars in (b) and (c) are 1 μm, that is, the domain width is 500 nm. d Scanning electron microscopy image of the active area of the fabricated graphene/BFO device. The fake color denotes on the graphene on the BFO film. e Schematic of the graphene plasmon resonator architecture for a plane wave normally infrared incidence. GSPP represents graphene surface plasmon polaritons. a and d represent the period of polarized strips (length of adjacent upward and downward domains) and the width of the ferroelectric domain stripes, respectively. f Simulated electric field intensity for graphene plasmon resonator by a three-dimensional model. The excited GSPP is highly confining in the borders of upward/downward domains at the graphene/BFO interface. SLG denotes single-layer graphene.