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CaCu 3 Ti 4Àx Y x O 12 (0 x 0.12) ceramics were fabricated with conventional solid-state reaction method. Phase structure and microstructure of prepared ceramics were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The impedance and modulus tests both suggested the existence of two different relaxation behavior, which were attributed to bulk and grain boundary response. In addition, the conductivity and dielectric permittivity showed a step-like behavior under 405 K. Meanwhile, frequency independence of dc conduction became dominant when above 405 K. In CCTO ceramic, rare earth element Y 3þ ions as an acceptor were used to substitute Ti sites, decreasing the concentration of oxygen vacancy around grainelectrode and grain boundary. The reason to the reduction of dielectric behavior in low frequencies range was associated with the Y doping in CCTO ceramic.

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Fabry−Peŕot interference plays an important role in modulating the spectral intensity of optical response originating from light−matter interactions. Examples of such interference occurring in the substrate as the resonating cavity have been demonstrated and probed by two-dimensional layered materials. Similarly, the Fabry−Peŕot interference can occur and modulate the optical response in the heterostructure; however, this remains elusive. Herein, we observe the Fabry−Peŕot interference on photoluminescence (PL) and Raman spectra in monolayer WS 2 / SiP 2 heterostructures by varying the thickness of bottom SiP 2 from 2 to 193 nm, which serves as the Fabry−Peŕot cavity. Both the intensities of the PL spectra and the E 2g1 Raman mode of WS 2 /SiP 2 heterostructures first decrease to almost zero while displaying an interference increase at a SiP 2 thickness of 75 nm. Our findings clearly demonstrate the Fabry−Peŕot interference in the optical response of heterostructures, providing crucial information to optimize the optical response and paving the way toward photodetector applications.

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