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Equipped with a tilt mirror and micro-mirror replacing the moving mirror,a novel Fourier transform spectrometer is proposed based on programmable Micro-Electro-Mechanical Systems(MEMS) micro-mirror.Firstly,the working principle and the tolerance of the tilting mirror is analyzed systematically and validated experimentally.Theory results show that the limited tilt angle is 0.52° and the spectrum resolution is 8 nm in the near infrared region;while the limited tilt angle is 0.183°,the spectrum resolution is 3 nm in the visible region.Experimental measurement shows that the spectra can be reconstructed accurately in the tolerance of the tilting mirror with central wavelength 488 nm laser soure and polychromatic light soure,while distorted badly out of the tolerance range.

Long-range surface plasmon polariton (LRSPP) modes in an asymmetrical system, in which the thin metal fllm is sandwiched between a semi-inflnite substrate and a high permittivity polymer fllm with a flnite thickness, are theoretically calculated and analyzed. Due to the high permittivity of the polymer fllm, at proper polymer fllm thicknesses, the index-matching condition of the dielectrics at both sides of the metal can be satisfled for supporting LRSPP modes, and the electromagnetic fleld above the metal can be localized well. It is found that these LRSPP modes have both long propagation lengths and subwavelength mode expansion above the metal at the optimal polymer fllm thicknesses. Furthermore, the requirements on the refractive index and the thickness of the polymer fllm to support LRSPP modes at the optimal thicknesses are found to be not critical.

Compared with conventional edge-emitting semiconductor lasers, vertical-cavity surface-emitting lasers (VCSELs) exhibit many advantages such as low power consumption, low threshold current, single longitudinal-mode operation, circular output beam with narrow divergence, on-wafer testing capability, high bandwidth modulation, low cost and easy large-scale integration into two-dimensional arrays, etc. VCSELs have been widely adopted in various applications such as optical communication, optical storage, parallel optical links, etc. At the same time, the rich dynamic characteristics of VCSELs have always been one of the frontier topics in the field of laser research, and many theoretically and experimentally investigated results have been reported. For theoretically investigating the dynamical characteristics of VCSELs, the spin-flip model (SFM) is one of most commonly and effectively used methods. In order to accurately predict the nonlinear dynamical performance of a 1550 nm-VCSEL, six characteristic parameters included in the rate equations of the SFM need to be given accurately. The six characteristic parameters are the decay rate of field k, the decay rate of total carrier population N, the linear anisotropies representing dichroism a, the linear anisotropies representing birefringence p, the spin-flip rate s, and the linewidth enhancement factor . In this work, through experimentally analyzing the output performances of a 1550 nm-VCSEL under free-running and parallel polarized optical injection, such six characteristic parameters included in the SFM are extracted first in the case that the temperature of the VCSEL is set to be 20.00℃. Furthermore, through gradually increasing the temperature of the 1550 nm-VCSEL from 10.00℃ to 30.00℃, the dependence of the six characteristic parameters on the temperature of the 1550 nm-VCSEL is investigated emphatically. The results show that with the increase of temperature of the 1550 nm-VCSEL, the linear anisotropy representing birefringence p behaves as an increasing trend, and the linewidth enhancement factor shows a decreasing trend. However, the other four characteristic parameters present complex varying trends with the increase of the temperature of the 1550 nm-VCSEL. The research in this paper is helpful in accurately understanding and controlling the dynamical characteristics of the VCSEL, and we hope that it can give a guidance for practical applications.

In order to prepare black silicon material with excellent optical absorption performance for solar cell application, a micro/nano bilayer-structure is formed on the surface of textured silicon wafer by a silver assisted chemical etching method. It is found that the deeper nanoholes could form as the etching time is longer, and the surface reflectivity is reduced obviously due to the increased time of photon reflection from the nanowires. The incident light reflectivity of the prepared black silicon is significantly reduced to 2.3%, showing obviously better optical reflectance characteristics than general monocrystalline silicon wafer, especially in a wavelength range of 300-830 nm. Considering the fact that a large number of carrier recombination centers is introduced into the nanostructured crystal silicon surface, BiFeO3/ITO composite film is coated on the surface of the black silicon solar cell by magnetron sputtering process to optimize the surface defect states and improve the cell performance. The experimental results show that the lengths of the nanowires are predominantly in a range of 180-320 nm for the prepared black silicon with micro/nano double-layer structure. The reflectivity of the incident light is below 5% in a wavelength range from 300 nm to 1000 nm, and reaches a maximal value at about 700 nm. The reflectance increases slightly as BiFeO3/ITO composite film is coated on the surface of black silicon solar cell, but it is still much lower than that of general monocrystalline silicon solar cell. The open circuit voltage and short circuit current density of the black silicon solar cell increase respectively from 0.61 V to 0.68 V and from 28.42 mA/cm2 to 34.57 mA/cm2 after it has been coated with BiFeO3/ITO composite film, and the photoelectric conversion efficiency of the cell increases from 13.3% to 16.8% accordingly. The improvement in performance of black silicon solar cell is mainly due to the promotion of effective separation of photogenerated carriers, thereby enhancing the spectral response of black silicon solar cell in the whole wavelength range. This indicates that the spontaneously polarized BiFeO3 film can play a better role in improving the surface properties of black silicon solar cell. On the other hand, for the BiFeO3 film deposited on the surface of black silicon, a spontaneous polarization positive electric field could be produced, pointing from the film surface to the inside of the solar cell. This polarization electric field could also act as part of built-in electric field to contribute the photoelectric transformation of the black silicon solar cell, leading to the open circuit voltage of cell increasing from 0.61 V to 0.68 V.

Silver nanostructures (Ag nanoparticles, Ag@SiO2 core-shell nanoparticles & Ag nanowires) were firstly added into aluminum oxide isopropanol solution to form cellular Al2O3 mesoporous layers for perovskite solar cell applications, respectively. Then CH3NH3PbI3 organic-inorganic hybrid perovskites were fabricated and attached to this matrix. Absorption spectra of Al2O3/CH3NH3PbI3 composite and CH3NH3PbI3 were found to be basically the same in the visible region, indicating that Al2O3 had less impact on the absorption performance of CH3NH3PbI3. However, the incorporation of silver nanostructures could significantly improve the absorption properties of the perovskites, and the best performance could be achieved with the concentration ratios of Ag nanoparticles, Ag@SiO2 core-shell nanoparticles and Ag nanowires of 0.15, 0.3 and 0.15, respectively. Further increasing the concentration of silver incorporation 第 9期 檀满林, 等: 银纳米相吸收增强型钙钛矿太阳电池薄膜的制备及性能研究 909 would probably cause halogenation and reduce the absorption properties of CH3NH3PbI3. In addition, the efficiency of perovskite solar cell could be improved from original 6.28% to 7.09% after addition of Ag@SiO2 core-shell nanoparticles. In contrast, the incorporation of Ag nanoparticles & nanowires tended to reduce the short circuit current density and conversion efficiency of the fabricated solar cells, because they could prolong the internal carrier transport path and hence increase the recombination probability of the electron-hole pairs.

Spin-flip model (SFM) is a mostly used approach to analyzing the nonlinear dynamics of vertical-cavity surface-emitting laser (VCSEL), and therefore the value selections of some key parameters in this model are crucial. In this work, based on experimentally measured dynamical characteristics of a 1550 nm vertical-cavity surface-emitting laser (1550 nm-VCSEL) under free running and parallel optical injection, some key parameters (field decay rate k, total carrier decay rate N, linewidth enhancement factor , active medium birefringence rate p, spin relaxation rate s, and active medium linear dispersion rate a) are estimated. Through experimentally measuring the noise spectrum of the laser, the relaxation oscillation frequency and the damping rate of the relaxation oscillations are calculated, and the photon lifetime can be preliminary estimated. After further amending the photon lifetime by considering the effect of the gain saturation on the damping rate of the relaxation oscillations, the value of k is determined. Based on the function relation between the laser relaxation oscillation frequency and the electrical pumping, the value of N is obtained. By experimentally acquiring the dynamical distribution mapping of the laser under parallel optical injection, the minimum Hopf bifurcation point of the Hopf bifurcation curve can be found, and then the value of is roughly estimated. According to the frequency difference between the two polarization components of the laser in the measured optical spectrum, the value of p can be calculated. The value of s is obtained by using the relationship between s and p. On the basis of the above determined parameter values, the value of a can be specified by numerically simulating the optical spectrum of the laser and comparing with experimentally obtained results. Moreover, by comparing the experimentally measured dynamical mapping of optical injection VCSEL with corresponding dynamical mapping simulated on the basis of the above mentioned parameters, the value of is rectified. Finally, further simulated results agree with relevant experimental observations.

Europium ions doped yttrium vanadate (YVO4: Eu) has excellent emission properties for down-conversion applications. However, the serious surface defects of YVO4: Eu hinder the improvement of luminescent efficiency. In order to improve the particle size distribution and morphology of YVO4: Eu nano-powders, mono-dispersed spherical YVO4: Eu@SiO2 core-shell structure materials were prepared by coating a layer of YVO4: Eu onto the surface of SiO2 microspheres. With the shell-core ratio setting as 0.6, the luminescence intensity of YVO4: Eu@SiO2 core-shell structure composite could reach up to more than 90% of pure YVO4: Eu nano-powder. Furthermore, the prepared YVO4: Eu@SiO2 core-shell structure films were used as down-conversion materials for amorphous silicon thin film solar cells. The cell parameters such as short current density and photoelectric conversion efficiency increased from original 6.694 mA/cm and 9.40% to 8.417 mA/cm and 10.15%, respectively. Thus YVO4: Eu@SiO2 core-shell configuration can be fabricated from YVO4: Eu and SiO2 microsphere to avoid agglomeration. 第 10 期 檀满林, 等: YVO4: Eu@SiO2 下转换发光特性及其太阳电池应用研究 1111 The prepared YVO4: Eu@SiO2 core-shell structures have regular morphology and uniform particle sizes, which are suitable to be used as down-conversion light emitting layer in amorphous silicon solar cells.

Due to the potential applications in optical storage, optical logic gates and all-optical signal shaping, the polarization switching (PS) and bistability (PB) of vertical-cavity surface-emitting lasers (VCSELs) under external disturbance have attracted much attention. In this work, based on the spin-flip model, the characteristics of PS and PB in a variable-polarization optical injection 1550 nm VCSEL (VPOI-1550 nm-VCSEL) are investigated numerically. In this scheme, the output from a master tunable laser passes through a rotating polarizer, an optical isolator (ISO), and a neutral density filter, then is injected into a 1550 nm-VCSEL. The polarization angle and power of the injection light are controlled by the RP and ISO, respectively. The results show that for a free-running 1550 nm-VCSEL, the parallel polarization-mode (Y polarization-mode) is lasing while the orthogonal polarization-mode (X polarization-mode) is suppressed in the 1550 nm-VCSEL. After introducing a variable-polarization optical injection, for a given frequency detuning Δν (defined as the frequency difference between the injection light and the X polarization mode), type I PS occurs during continuously increasing the injection power and type II PS occurs in the inverse process if the polarization angle θp of the injection light (defined as the angle difference between the polarization direction of injection light and Y polarization mode of the 1550 nm-VCSEL) is large enough. Moreover, the injection power required for generating type I PS is different from that for generating type II PS, namely PB is observed. When Δν is fixed, with the increase of θp, the injection power for the occurrences of the two types PS and the width of PB decrease. For a larger value of |Δν|, the injection power for the occurrence of type I PS is higher meanwhile the width of the PB is larger than that for a relatively small value of |Δν|. On the other hand, for a given injection power, type I PS, type II PS, and corresponding PB can also be observed in the 1550 nm-VCSEL through continuously increasing and reducing θp within the range from 0° to 90° under an appropriate Δν. For a relatively small |Δν|, the value of θp required for the occurrence of type I is similar to that for type II PS, which results in the very narrow width of the PB. Contrastively, for a relatively large |Δν|, the values of θp required for the occurrences of the two types PS and the width of PB severely fluctuate with the variation of Δν. Therefore, for the fixed parameters of the 1550 nm-VCSEL, through adjusting the power and polarization angle of the injection light, the performances of the PS and PB can be optimized. It is expected that this work can provide an effective guidance for optimizing the VCSEL-based bistable devices.

The coupling interaction between an individual optical emitter and the propagating surface plasmon polaritons in a graphene microribbon (GMR) waveguide is investigated by numerical calculations, where the emitter is situated above the GMR or in the same plane of the GMR. The results reveal a multimode coupling mechanism for the strong interaction between the emitter and the propagating plasmonic waves in graphene. When the emitter is situated in the same plane of the GMR, the decay rate from the emitter to the surface plasmon polaritons increases more than 10 times compared with that in the case with the emitter above the GMR.

Surface of Zinc oxide (ZnO) nanoparticles prepared by Sol-Gel method was modified by a polymer reactant, PEG (polyethylene glycol, Mw=2000). The structure and optical properties of the PEG modified nanoparticles were then investigated by X-ray diffraction, Fourier transform infrared spectroscopy, photoluminescence spectroscopy, transmission electron microscopy. Results showed that the added PEG polymers were successfully coated on the surface of ZnO nanoparticles, without obvious variation being found in the ZnO crystal structure. The ZnO particles tend to have a smaller size, better stability and better dispersible uniformity after PEG coating. Furthermore, a defect state emission peak with significantly reduced intensity was found at the range of 400-500 nm in photoluminescence spectra, indicating that the surface defects of ZnO nanoparticles could be well improved by PEG modification.

Using an ultracompact groove-slit-groove (GSG) structure, a refractive index sensor with a broadband response is proposed and experimentally demonstrated. Due to the interference of surface plasmon polaritons (SPPs), the transmission spectra in the GSG structure exhibit oscillation behaviors in a broad bandwidth, and they are quite sensitive to the refractive index of the surroundings. Based on the principle, the characteristics of its refractive index sensing are demonstrated experimentally. In the experiment, the structure is illuminated with a bulk light source (not a tightly focused light source) from the back side. This decreases the difficulty of the experimental measurement and can protect strong light sources from damaging the detection samples. Meanwhile, the whole structure of the sensor can be made more ultracompact without considering the influence of the incident waves.

In this paper, we investigate the charge sharing collection induced by heavy ion radiation in a tripe well CMOS technology with n+ deep well though 3-D TCAD device simulation. Result shows that n+ deep well will induce the parasitical NPN bipolar transistor, and therefore enhance the charge sharing between NMOS remarkably. The enhancement factor is 24 times that in PNP bipolar in dual well technology. Furthermore, the effects of n-well contact and p-well contact on NPN bipolar are studied. The result shows that the NPN bipolar enhancement factor will decrease with the increase of p-well contact area and with the decreasing of its distance to device, while the NPN bipolar enhancement factor will increase with the increase of n-well contact area.

The optical characteristic of the nanohole array film is analyzed by using rigorous coupled wave, and the nanohole array film is proposed to serve as photovoltaic device anti-reflection film to improve the device absorption and efficiency. According to theoretical analysis, nanohole array anti-reflection film has a better anti-reflection effect than the monofilm and can better enhance the photovoltaic device's efficiency, especially in a speetral range of 400 nm600 nm; the optimal period of the nanohole array is 500 nm, the optimal filling factor of the nanohole array is 0.2 and the optimal thickness of the nanohole array is 110 nm. In order to testify the optical effect of nanohole array, the nanohole arrays of different sizes are made by the micro-nano processing technology in the anti-reflection film of the 200 m Si Detector, and a relevant experimental system is set up. With the optimized nanohole arrays, the short circuit currents of the experimental sample are increased ～6% in a 4001100 nm spectral range, especially, increased ～15% in a 400 nm-600 nm spectral range.

Annular gate nMOSFETs are frequently used in spaceborne integrated circuits due to their intrinsic good capability of resisting total ionizing dose (TID) effect. However, their capability of resisting the hot carrier effect (HCE) has also been proven to be very weak. In this paper, the reason why the annular gate nMOSFETs have good TID but bad HCE resistance is discussed in detail, and an improved design to locate the source contacts only along one side of the annular gate is used to weaken the HCE degradation. The good TID and HCE hardened capability of the design are verified by the experiments for I/O and core nMOSFETs in a 0.18 μm bulk CMOS technology. In addition, the shortcoming of this design is also discussed and the TID and the HCE characteristics of the replacers (the annular source nMOSFETs) are also studied to provide a possible alternative for the designers.

We propose a nondestructive method to characterize the quantitative bonding strength at a bonded solid-solid interface by a contact acoustic nonlinearity (CAN) microscope. The principle of the CAN microscope is briefly described. The vibration amplitude of the incident focusing wave at the bonded interface is calculated, the standard bonding strength with a complete bonding state is established by the tension test, and the CAN parameter is calibrated. The quantitative contour of bonding strength at the interface could be obtained. The experimental contours of two samples are also presented.

Based on full 3D finite element method simulations, the transmission of a dielectric-loaded surface plasmon polariton waveguide (DLSPPW) based 1/4 circle is calculated for a 90° bend model and a 270° bend model, respectively. It is found that the 270° bend model gives almost pure bending loss while the 90° bend model contains additional coupling loss. The models are applied to deduce the loss and unloaded quality factor of DLSPPW based waveguide ring resonators (WRRs) and the results of the 270° bend model agree well with direct simulating results of the WRRs. Thus the 270° bend model gives a fast and simple way to calculate bending loss and it is helpful for WRR design because no wavelength scan is needed.

We present a unique method to describe the bonding strength at a bonded solid–solid interface in a multilayered composite material by contact acoustic nonlinearity (CAN) parameter. A CAN model on the bonded solid–solid interface is depicted. It can be seen from the model that CAN parameter is very sensitive to the bonding strength at the interface. When an incident focusing acoustic longitudinal wave scans the interface in two dimensions, the transmitted wave can be used to extract CAN parameter. The contour of the bonding strength for a sample is obtained by CAN parameter. The results show that the region with weak bonding strength can be easily distinguished from the contour.

A simple, high efficiency and mini-sized surface plasmon polariton (SPP) modulator based on electro-optic polymer is proposed. The modulator is constructed by metallic stripes of Mach-Zender (M-Z) interferometric structure and with electro-optic polymer surrounding the stripes. The reflectivity index of the electro-optic polymer is modulated when the modulating voltage is applied to the two arms of the M-Z interferometer. Through the M-Z interferometer, the modulation of the reflectivity index can be transferred into the modulation of the SPP intensity. By calculating the electric field near the metallic stripes and taking the distribution of SPP field into account, the working principle of the SPP modulator is demonstrated in detail and the half-wave modulating voltage is evaluated as 2.8V.