Wavelength sensitivity reconfigurable SPR photodetector with a blazed grating profile.

Surface plasmonic detectors based on one-dimensional half-wavelength gratings have attracted attention due to their wavelength- or polarization-specific photodetection. Although the effect of a grating period and a grating depth on the photoelectric conversion of 1D half-wavelength grating-based surface plasmon resonance (SPR) detectors has been discussed thoroughly in recent years, the effect of different grating profiles on device performance is still limited to the rectangular shape. In this article, we proposed a wavelength sensitivity reconfigurable photodetector enhanced by SPR with a blazed grating profile. The gold layer was fabricated on a silicon-based blazed grating to form a Schottky barrier and act as an SPR coupler. By measuring the photocurrent in the range of -58° to -48°of an incident angle, the peak shifts of a photocurrent signal waveform are found to depend on the wavelength over 800-1000 nm.

Giant intrinsic piezoelectricity in 2D hybrid organic-inorganic perovskites [C6H11NH3]2MX4 (M = Ge, Sn, Pb; X = Cl, Br, I).

2D-piezoelectric materials are attractive for micro-electromechanical systems (MEMS), medical implants and wearable devices because of their numerous exceptional properties. 2D-hybrid organic-inorganic perovskites (HOIPs) have attracted extensive research interest due to their merits of structural diversity, good mechanical flexibility, and ease of fabrication. The electronic energy band, charge density and the elastic properties of 2D-HOIP-[C6H11NH3]2MX4 (M = Ge, Sn, Pb; X = Cl, Br, I) were investigated using first-principles calculations. The excellent piezoelectricity of 2D-HOIP-[C6H11NH3]2MX4 has been analyzed in detail. More importantly, 2D-[C6H11NH3]2MX4 have giant intrinsic positive and negative out-of-plane piezoelectric coefficients under the effect of van der Waals interaction. The d31 and d32 of [C6H11NH3]2SnBr4 are 82.720 pm V-1 and -36.139 pm V-1, respectively, which are among the largest piezoelectric coefficients among all kinds of atomic-thick 2D materials reported. The high flexibility together with the giant out-of-plane piezoelectricity would endow these 2D-HOIP-[C6H11NH3]2MX4 with potential applications in ultrathin piezoelectric cantilever and diaphragm devices.