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As the important electric loss of a graphene resonator, intrinsic current loss has received increasing attention, but the existing research is limited to qualitative analysis and approximate calculation. Based on the microscopic behavior of carriers, we have accurately established the calculation model of induced current loss, which is in good agreement with the existing experimental results. Compared with the previous models, the model in this work can not only fit the inverse V-shaped Q − V dc curve well but also be compatible with the V-shaped Q − V dc curve, which is beyond the reach of the previous models. In addition, the calculation results show that selecting the appropriate gate voltage combination when stimulating the graphene resonator can increase the quality factor by nearly 1–2 orders of magnitude. Furthermore, we reasonably explain the importance of DC gate voltage applied in the experiment compared with the case of non-DC gate voltage. This work realizes the accurate calculation of intrinsic current loss and is of great significance for reducing the intrinsic current loss in the practical application of graphene resonators.

The stellar/inertial integrated navigation system, which combines the inertial navigation system (INS) and the star tracker, can restrain the accumulated INS errors. In the traditional loosely coupled stellar/inertial integration method, the star tracker needs to observe more than two navigation stars on an image for attitude determination and to use the attitude information as the observation to estimate the systematic errors of the INS. However, under strong background radiation conditions, the star number in the field of view (FOV) usually drops below 3; thus, the loosely coupled method fails to work. To overcome this difficulty, an improved tightly coupled stellar/inertial integration method based on the observation of the star centroid prediction error (SCPE) is proposed in this paper. It calculates the difference between the extracted star centroid and the predicted star centroid, namely, the SCPE, as the observation and then estimates the INS errors with a Kalman filter. Numerical simulations and ground experiments are conducted to validate the feasibility of the tightly coupled method. It is proved that the proposed method, which makes full use of all star observation information, can improve the navigation accuracy compared with the loosely coupled method and is more robust when there are not enough stars in the FOV.

The twist-angle dependence of exciton absorption in a molybdenum disulfide (MoS2)/graphene heterostructure (MGH) is reported. Using photoluminescence (PL) spectroscopy, we found that, as the twist angle increased, the MGH demonstrated an enhancement of PL intensity and a peak position blueshift, indicating that the exciton radiative recombination was positively correlated with the twist angle. In addition, optical reflectance measurements were performed in order to investigate the exciton absorption in the MGH. It was found that the reflectance of MGH samples was twist-angle dependent at wavelengths of 620 and 670 nm, which corresponds to the PL peak positions of MoS2. This was attributed to the change in interlayer charge transfer for different twist angles. Our findings confirm the tunability of the electronic structure in MGHs via the interlayer twist, which enriches our understanding of interlayer coupling and is important for the future development of electronic and optoelectronic devices based on 2D material heterostructures.

Graphene photodetectors are highly attractive owing to its ultra-fast and wide-range spectral response from visible to infrared benefit from the superior carrier mobility and the linear dispersion with zero bandgap of graphene. The application of graphene photodetectors however is seriously limited by the low intrinsic responsivity in the order of ∼10 mA/W. Here, we demonstrate photogating field-effect transistors based on pure monolayer graphene with simple device structures. The light absorption in the heavily n-doped silicon/silicon oxide (Si/SiO2) substrate generates an additional photovoltage that effectively modulates the conductance of graphene, leading to room temperature graphene photodetectors with high responsivity of ∼500 A/W for 450 nm light and ∼4 A/W for 1064 nm light, respectively. The generated photocurrent changes with applied gate voltage and shows a strongly nonlinear power dependence. Meanwhile, the photoresponse of graphene exhibits a cut-off wavelength of ∼1100 nm, confirming the dominance photogating effect caused by light absorption in Si/SiO2 substrate. Considering the great compatibility of graphene to Si technology, our result paves a way for high-performance chip-integrated photodetectors.

Plasmon was probed from graphene which was grown by chemical vapor deposition using terahertz time-domain spectroscopy at room temperature. Graphene was laid on a resonant cavity, and metal grating was then deposited on top of them. For the THz light polarized along the grid fingers, the optical conductivity of graphene changed from Drude response into strongly Lorentz behavior with a peak formed in the THz-region. These experimental results are highly consistent with the theoretical prediction of a single layer graphene. It confirms that the graphene plasmon frequency can be tuned by the length of grating. Moreover, the extinction in the transmission of single-layer graphene can also be increased beyond 60%.

The metal-oxide-graphene heterostructures have abundant physical connotations. As one of the most important physical properties, the electric transport property of the gold-chromium oxide-graphene heterostructure has been studied. The experimental measurement shows that the conductive mechanism is dominated by the space-charge-limited transport, a kind of bulk transport of an insulator with charge traps. Combining the theoretical analysis, some key parameters such as the carrier mobility and trap energy also are obtained. The study of the characteristics of the metal-oxide-graphene heterostructures is helpful to investigate the graphene-based electronic and photoelectric devices.

We theoretically demonstrate a polarizer with an electrically controllable polarizing direction in the far infrared range using two orthogonal periodic arrays of graphene ribbons, which have different widths and are supported on a dielectric film placed on a thick piece of metal. The operation mechanism originates from the polarization-dependent resonant absorption of the two orthogonal graphene ribbons, which can be respectively controlled with different external bias voltages. The operation wavelength can be expanded to terahertz (THz) radiation.

The metal/graphene contacts play a very important role in the performance of graphene-based devices. We report here a unique observation of current-induced doping in graphene transistors. The charge carrier type and the concentration in graphene can be manipulated by the current flowing through the graphene device, arising from the asymmetrical metal/graphene barriers between the source and drain electrodes and the accompanied current crowding effect.

The influence of carriers on the piezoelectric potential in a bent ZnO nanorod is investigated using finite difference method. The distributions of carriers and the electrical potential in the nanorod are obtained. The results shows that the positive piezoelectric potential in stretched side of the bent nanorod is significantly screened by the carriers and the negative potential in compressed side is well preserved when considering a moderate carrier concentration of 1×1017 cm−3. The calculation results agree with the experimental results that only negative pulses are observed in the nanogenerator experiment using the as-grown ZnO nanorods. Further investigation shows that when the carrier concentration is 1×1018 cm−3, the piezoelectric potential in the nanorod is almost completely screened by the redistributed carriers.