Design and calculation of photoelectric properties of resonance enhanced InAs/GaSb type-II superlattices photodetectors with diffraction rings structure.

The resonance enhanced InAs/GaSb type-II Superlattices (T2SLs) infrared detectors with diffraction rings is designed, and the photoelectric characteristics are calculated and studied in this paper. The diffraction rings are designed on the top surface of T2SLs detector to control the incident light inside the device by forming the resonant cavity. We designed the structure of the conventional PIN InAs/GaSb T2SLs photodetector, calculated the energy band structure of the absorption layer, and analyzed the influence of the thickness of the absorption layer on the photoelectric performance. It is proved that blindly increasing the thickness of the absorption layer cannot effectively improve the device performance. We further studied the quantum efficiency (QE) and electric field distribution of the device after adding the diffraction ring structure. The results show that the structure with diffraction rings can significantly improve the QE of the photodetector without increasing the dark current. The interaction between the diffraction ring and the metal contact layer will enhance the localization of the electric field and further increase the light absorption between the semiconductor layers.

Wrinkle Clamp Down on Structure Crack Strain Sensor Based on High Poisson's Ratio Material for Home Health Monitoring and Human-Machine Interaction.

Flexible wearable crack strain sensors are currently receiving significant attention because they can be used in a wide range of physiological signal monitoring and human-machine interaction applications. However, sensors with high sensitivity, great repeatability, and wide sensing range remain challenging. Herein, a tunable wrinkle clamp down structure (WCDS) crack strain sensor based on high Poisson's ratio material with high sensitivity, high stability, and wide strain range is proposed. Based on the high Poisson's ratio of the acrylic acid film, the WCDS was prepared by a prestretching process. The wrinkle structures can clamp down the crack to improve the cyclic stability of the crack strain sensor while maintaining its high sensitivity. Moreover, the tensile properties of the crack strain sensor are improved by introducing wrinkles in the bridge-like gold stripes connecting each separated gold flake. Owing to this structure, the sensitivity of the sensor can reach 3627, stable operation over 10 000 cycles is achieved, and the strain range can reach about 9%. In addition, the sensor exhibits low dynamic response and good frequency characteristics. Because of its demonstrated excellent performance, the strain sensor can be used in pulse wave and heart rate monitoring, as well as posture recognition and game control.

Flexible Triboelectric Tactile Sensor Based on a Robust MXene/Leather Film for Human-Machine Interaction.

With the rapid development of Internet of Things (IoT) technology in recent years, self-actuated sensor systems without an external power supply such as flexible triboelectric nanogenerator (TENG)-based strain sensors have received wide attention due to their simple structure and self-powered active sensing properties. However, to satisfy the practical applications of human wearable biointegration, flexible TENGs impose higher requirements for establishing a balance between material flexibility and good electrical properties. In this work, the strength of the MXene/substrate interface was greatly improved by utilizing leather with a unique surface structure as the substrate material, resulting in a mechanically strong and electrically conductive MXene film. Due to the natural fiber structure of the leather surface, the surface of the MXene film with a rough structure was obtained, which improved the electrical output performance of the TENG. The electrode output voltage of MXene film on leather based on single-electrode TENG can reach 199.56 V and the maximum output power density can reach 0.469 mW/cm2. Combined with laser-assisted technology, the efficient array preparation of MXene and graphene was achieved and applied to various human-machine interface (HMI) applications.

Full-Stokes imaging polarimetry based on a metallic metasurface.

We use a single-layer thick metallic metasurface to design the 0-,45- and 90-degree polarizers with transmission efficiencies exceeding 95% based on the bright electric dipole resonance and dark magnetic dipole resonance. In addition, we utilize a bilayer metallic metasurface (forming an efficient Fabry-Perot resonator) to propose a circularly polarizing dichroism waveplate (CPDW). The circular polarization dichroism (CPD = IRCP - ILCP.) in the transmission mode at 1.6 µm wavelength reaches 89% and the extinction ratio (ER = IRCP/ILCP) is 830:1. These four polarizing elements are integrated to form a full Stokes pixel that almost accurately measures arbitrary polarized light at λ0 = 1.6 µm (including elliptically polarized light).