最新刊期
卷 40 ， 期 2 ， 2019
- 摘要：Because the 1.55 m band is widely used in the communication field, in order to explore the influence of different growth temperatures on the morphology of InN quantum dots(QDs), and to realize the 1.55 m luminescence of self-assembled InN QDs, the droplet epitaxy and physical properties of InN QDs were investigated. Firstly, the InN QDs structure was grown at three different temperatures by droplet epitaxy on a GaN template using radio frequency plasma-assisted molecular beam epitaxy(PA-MBE) technique. During the growth process, the sample was in-situ detected by RHEED. The AFM results show that the size of quantum dots increases and the density decreases with the growth temperature increasing. The InN QDs were observed at the growth temperatures of 350℃ and 400℃. No InN quantum dots were observed at temperature 450℃. When the growth temperature is 400℃, the QDs have the best morphology and the QDs density is 6108/cm2. The temperature dependent PL was measured on the sample grown at 400℃, and the 1.55 m emission from the InN QDs is successfully obtained. With the increase of measured temperature, the emission peaks of quantum dots have a S-curve change:from a red shift to a blue shift and last a red shift. These InN QDs are expected to be used in the quantum communication field in the future.关键词：InN;quantum dot(QD);molecular beam epitaxy(MBE);droplet epitary(DE)199|163|0更新时间：2020-08-12
- 摘要：The Ce,Pr:GAGG powders were prepared by chemical co-precipitation and one step calcinations. The surface morphologies and luminescence properties of the samples were analyzed by XRD, SEM and fluorescence spectrometer. The effects of calcination temperature and the introduction of oxalate into precipitant on the luminescent properties of powders were investigated. The results showed that the precursor transformed into GAGG phase after being calcined at 950℃ for 3 h.The co-doping of Pr3+ and Ce3+ did not change the phase structure of the matrix. After the precipitation agent was introduced into ammonium oxalate, the emission spectrum intensity of the powder increased from 333 573 a.u to 420 894 a.u, precipitation agent introduced oxalate can improve powder luminescence performance. The fluorescence lifetime test showed that the incorporation of Pr3+ in Ce:GAGG can reduce the fluorescence lifetime of Ce3+ and the decay time is 35.43 ns.关键词：gadolinium-aluminum-gallium-based garnet;nanopowder;co-doped;emission spectrum;decay time170|750|2更新时间：2020-08-12
- 摘要：Upconversion nanocrystals(UPCNs) from hexagonal phase LaF3 (β) to cubic phase KLaF4(α) or hexagonal phase(KLaF4)1.5(β) were prepared by simply tuning the molar ratio of KF to RE(RE=La, Yb, Er), reaction temperature and reaction time in ethlene glycol(EG) and 1-hexanol (HA) mixed solvents via a facile hydro/solvothermal method. The β-LaF3 to α-KLaF4 or β-(KLaF4)1.5 transformation process was studied by X-ray diffraction(XRD), fluorescence spectrophotometer with an external 980 nm single-wavelength diode laser and transmission electron microscopy(TEM) techniques. The results indicate that the hexagonal phase of LaF3 nanosheet was synthesized when the ratio of KF/RE was 2.25. With the ratio of KF/RE increased to 3.00, the approximate spherical cubic phase of KLaF4 was obtained. The cubic phase of KLaF4 completely transforms into the hexagonal phase of (KLaF4)1.5 when the ratio of KF/RE was 4.25. The red and green emission are corresponding to the transitions 4S3/2, 2H11/2→4I15/2(Green) at 522 nm and 544 nm, 4F9/2→ 4I15/2(Red) at 655 nm of Er3+ ions, respectively.关键词：hydro/solvothermal method;molar ratio of KF/RE;rare earth fluoride;upconversion luminescence117|38|0更新时间：2020-08-12
- 摘要：The sub-micron size diamond powders are ideal abrasives for ultrafine rubbing and polishing. However, the synthesis and preparation of high-quality sub-micron size diamond powders are still faced with lots of difficulties and challenges until now. High-quality diamond powders with sub-micron size were synthesized successfully from naphthalene at a temperature of 1 700℃ and a pressure of 11 GPa without using metal-catalysts. The phase purity of the synthesized diamond powders was extremely high. Most of the diamond grains were euhedral crystals showed well-developed crystal morphology and dispersed to each other. The frequency distribution of the diamond grain size was in positive skew distribution, values of the mean, median and mode were 158.1, 221.5, 262.5 nm, respectively. For lognormal distribution, the expected value of the diamond grain size and the standard deviation were (243.3±4.2) nm and (122.3±5.4) nm, respectively. Nearly 96% of the diamond grains were distributed in the sub-micron size range. It may provide an effective way for the synthesis and preparation of high-quality sub-micron size diamond powders.关键词：sub-micron;diamond;high pressure high temperature171|166|0更新时间：2020-08-12
- 摘要：Europium(Ⅲ)-doped Na8.33La1.67(SiO4)6O2 have been synthesized by solid stated method. The crystal structure has been detected by X-ray diffractometer and the photoluminescence properties have been obtained on Hitachi F4600. Under UV excitation, the emission of Na8.33La1.67-(SiO4)6O2:Eu3+ cover some sharp lines corresponding to the transitions of 5D0-7Fj(j=0, 1, 2, 3, 4), with the highest intensity at 615 nm ascribed to the transition of 5D0-7F2. Moreover, the emission intensity changes with the concentration of Eu3+. As the concentration is 15%, the optimal emission is obtained, which is concentration quenching. The phenomenon is due to the energy migration between Eu3+ ions. And the interaction mechanism between Eu3+ ions is calculated, which is exchange interaction.关键词：red phosphor;solid state method;energy migration;white LED;Na8.33La1.67(SiO4)6O2:Eu3+140|152|2更新时间：2020-08-12
- 摘要：Tin oxide thin films were prepared on glass substrates by spin coating, then, films were annealed at different temperatures in the air. The morphology, structural characteristics, optical properties and electrical properties of the films were characterized by atomic force microscope(AFM), X-ray reflection system(XRR), FT-IR, X-ray diffraction(XRD), UV-visible spectrophotometer, four-probe tester and Kelvin Probe, and the effect of annealing temperature on the quality of film and its mechanism have been studied. The results show that, as the annealing temperature increases, the thickness of the films decreases, the content of organic in films reduces, and the density of the films increases, however, the surface roughness of the film increases. When the annealing temperature is 500℃, SnO2 crystals appear on the film, the (101), (110), (211) crystal phases appear. Transmittance of samples in the visible light region is above 90%. As the annealing temperature increases, the transmittance of the film in 400-800 nm band decreases first and then increases, and bandgap widths of the films are 3.840 eV(as-deposited), 3.792 eV(100℃), 3.690 eV(300℃), and 3.768 eV(500℃); the conductivity of the film increases, and the conductivity reaches 916 S/m at 500℃; the work function of the film increases and then decreases, and work function of the films is (4.61±0.005) eV(as-deposited), (4.64±0.005) eV(100℃), (4.82±0.025) eV(300℃), (4.78±0.065) eV(500℃).关键词：tin oxide thin film;spin coating;annealing;optical properties;electrical properties237|212|0更新时间：2020-08-12
- 摘要：A photocatalyst of titanium dioxide nanotube-graphene was prepared by hydrothermal method in this paper. The composites were characterized for further analyzation by X-ray diffractometry, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The photocatalytic properties were tested. The results show that the photocatalytic performance of titanium dioxide nanotube-graphene is higher than that of pure titanium dioxide nanotubes. Graphene is combined with titanium dioxide nanotubes to act as an electron acceptor, and the carrier mobility is improved, thereby improving photocatalytic performance.关键词：photocatalytic;graphene;titanium dioxide nanotube;hydrothermal172|158|5更新时间：2020-08-12
- 摘要：Large-scale promotion of "smart windows" is to conform to the trend of sustainable development. Tungsten trioxide(WO3) is an important electrochromic material for producing "smart window" but the mechanism of regulating the electrochromic properties of WO3 thin films remains to be further studied. WO3 films were prepared by spin-coating process. The thickness of films was measured by surface profiler. The crystallinity of films was measured by X-ray diffraction(XRD) and the surface morphology was measured by atomic force microscope(AFM) and scanning electron microscope(SEM). Finally, the transmittance of the films was measured by spectrometer. The experiment results indicated that the thickness of the films increased from 9.7 nm to 33.3 nm with the solution concentration increasing(0.2 mol/L to 1.0 mol/L), and the transmittance modulation capability of this film increased from 0% to 37.0%. The thickness of multiple spin-coated films increased linearly, and goodness of fit(R2) was 0.98. After 5 times of spin-coating, the transmittance modulation capability reached 51.3%. Both changing the concentration of solution and the times of spin-coating are the effective means to regulate transmittance modulation capability and it is of great significance to accurately regulate the transmittance modulation capability of the film to design the electrochromic devices for different application scenarios.关键词：thin film;tungsten trioxide;spin-coating;surface morphology;thickness;electrochromism253|256|3更新时间：2020-08-12
- 摘要：A series of Zn2GeO4:xMn2+ green long afterglow phosphors have been synthesized by high temperature solid-state reaction method. XRD results show that the main diffraction peaks of phosphors doped Mn2+ ions are basically consistent with those in standard card of Zn2GeO4 crystal, but there exists slightly red shift. SEM photos present the particle sizes of phosphors doped different Mn2+ ions are all enlarged compared to average grain size of Zn2GeO4 host. The intense 530 nm green emissions from Zn2GeO4:Mn2+ phosphors can be gained under 325 nm ultraviolet excitation and optimal Mn2+ doping concentration is 0.5%. At the same time, it is found that the afterglow time of Zn2GeO4:0.2Mn2+ phosphor exceeds 180 min under the condition of dark environment, and the internal mechanism of long afterglow luminescence of Zn2GeO4:Mn2+ phosphor is discussed in detail.关键词：Zn2GeO4:Mn2+ phosphor;red shift of diffraction peak;photoluminescence characteristics;long afterglow191|283|2更新时间：2020-08-12
Synthesis and Properties of Materials
- 摘要：In order to improve the beam quality of 976 nm wide stripe high power semiconductor laser, a beam quality measurement setup for high power semiconductor lasers is constructed based on the strict second moment theory. This setup is used to measure the beam waist position, beam waist size and far field divergence angle of 976 nm wide stripe high power semiconductor lasers prepared by our lab. The experimental result shows that with the increase of current from 1 A to 10 A, the fast axis beam width and far-field divergence angle increase slightly due to the anti-guidance effect,but the beam parameters change very small because of the strong refractive index guidance mechanism in the vertical direction. The beam quality is almost unchanged, when the beam quality factor M2 is only increased from 1.32 to 1.48. In slow axis direction, the beam width and far field divergence angle increase gradually with the increase of operating current due to the high-order mode lasing caused by the anti-guidance effect and the thermal lens effect. The beam quality becomes worse, when the beam quality factor M2 is increased from 5.44 to 11.76. The difference of the beam quality factor is compared with the definition of paraxial beam and non-paraxial beam. The results show that there is an obvious difference by different beam definitions in the fast axis direction and the paraxial beam definition is not suitable for the calculation. In the direction of slow axis, the results are approximately equal and can be approximately calculated by using the paraxial beam definition.关键词：semiconductor laser;general laser theory;lasers192|312|8更新时间：2020-08-12
- 摘要：In order to improve the efficiency of CIGS thin film solar cell, a novel AZO/patterned Ag/AZO multilayer front contact was investigated. In this architecture, middle Ag thin film is patterned, which has the identical shape and size with the metal grid of solar cell and under the metal grid. This architecture can increase the electrical properties when the transmittance is constant. The transmittance and sheet resistance of new architecture were compared with that of traditional front contact. In comparison with the solar cell with AZO and AZO/Ag/AZO front contact, the CIGS solar cell with new architecture shows the higher short circuit current and improves efficiency from 13.83% to 14.53%. The noval architecture can improve the efficiency of CIGS solar cell.关键词：CIGS;front contact;AZO/patterned Ag/AZO;AZO/Ag/AZO;sputtering149|304|2更新时间：2020-08-12
- 摘要：Novel tungsten-zinc-tin-oxide(WZTO) thin film transistors(TFTs) are fabricated by solution process and the influence of annealing temperatures on WZTO films and TFTs is thorough investigated. XRD results show that the WZTO films are amorphous when annealing temperature reaches 500℃. The W doping significantly reduced the surface roughness of the ZTO films and its roughness of root-mean-square decreased from 0.9 nm to less than 0.5 nm. The transmittance of WZTO is more than 85%. In addition, XPS analysis confirmed that annealing treatment remarkably improved the oxygen vacancy of WZTO film which resulted in the increase of carrier concentration in films. The threshold voltage of devices reduces from 8.04 V to 3.48 V. The mobility of devices changes with the increase of annealing temperatures and the ratio of ON-state current and OFF-state current is about 107.关键词：annealing temperatures;solution-processed;thin film transistors;WSnZnO170|203|1更新时间：2020-08-12
- 摘要：The optical properties, surface chemistry and band energies of PbS colloidal quantum dots (CQDs) passivated with tetrabutylammonium iodide(PbS-TBAI) and 1,2-ethanedithiol(EDT) were analyzed by absorption spectroscopy, Fourier transform infrared spectroscopy and cyclic voltammetry measurements. Also, the photovoltaic performance and air stability of PbS CQDs/ZnO nanoparticles heterojunction solar cells using PbS-TBAI, PbS-EDT and PbS-TBAI/PbS-EDT films as active layers respectively were investigated. The results showed that both TBAI and EDT ligands could achieve good ligand exchange with original oleic acid ligands on the surface of PbS CQDs, while a small number of residual oleic acid molecules remained in the PbS CQDs films. The conduction band minimum and valence band maximum of the PbS CQDs treated with TBAI are -3.86 eV and -5.12 eV, while they can be upshifted to -3.74 eV and -4.99 eV, respectively, for the PbS CQDs treated with EDT. The PbS-TBAI/PbS-EDT device exhibited the highest power conversion efficiency of 4.43% among these three type of devices. With the increase of air exposure time, the PbS-TBAI/PbS-EDT device exhibited similar performance evolution to the PbS-TBAI device and achieved its best performance after three days of air exposure. However, the PbS-EDT device showed poor air stability and its efficiency was reduced to a quarter of its initial value after three days of air exposure.This work is not only capable of deepening the understanding of the performance evolution of PbS-CQD solar cells, but also capable of guiding the further optimization of these devices.关键词：PbS colloidal quantum dots;solar cells;ligands;energy level structure;stability163|538|0更新时间：2020-08-12
- 摘要：Unlike conventional inorganic photodetectors in conjunction with optical filters or prisms to obtain wavelength selective response, photodetectors rely on organic semiconductors enable to facilitate wavelength selective absorption. In this article, a novel method and relative architecture are proposed to effectively enhance the peak absorption and decrease the full width at half maximum (FWHM) of the narrowband organic photodetectors. The architecture is combined with distributed Bragg reflector (DBR) and organic photodiode (OPD). An optical resonant is formed between the top contact and bottom contact of the OPD. The effects of the center wavelength of the DBR, the thickness of transparent top contact and the thickness of photoactive layer on the absorption performance of the organic photodetector were analyzed in detail by using the transfer matrix method. The simulation results indicate that FWHM less than 20 nm and absorption peak above 70% can be obtained with the Tamm plasmon polaritons resonant wavelength arisen nearby the optical bandgap of the photoactive layer. Red and NIR organic photodetectors can be obtained with photoactive layers of PTB7:PC71BM and PTB7-Th:IEICO-4F, respectively. The design concept combining materials and device structure allows for tuning response region from visible to NIR.关键词：photodetector;organic photodiode;narrowband response;Tamm plasmon polaritons189|403|0更新时间：2020-08-12
- 摘要：In order to improve the packaging quality and efficiency of semiconductor lasers, tube furnaces were introduced into the bulk package using fixtures. Since the quality of the package directly affected the output characteristics and service life of the semiconductor laser, the 808 nm chips were grown by MOCVD, and the influence of the tube furnace temperature and the packaging time on the package quality of the double-sided AuSn packaged semiconductor laser bar was analyzed. Using X-ray detection, junction voltage, photoelectric characteristics parameters and "smile" effect testing methods, the optimal package conditions for the tube furnace package semiconductor laser bars were determined, providing guidance for future industrialization.关键词：semiconductor laser;bar;AuSn solder;X-ray inspection;smile effect158|305|0更新时间：2020-08-12
- 摘要：Flexible organic light emitting diodes (FOLEDs) have shown broad prospects in flexible display, flexible lighting and wearable devices due to the advantages of good mechanical flexibility, low power consumption, low driving voltage, high color gamut, wide viewing angle, fast response, etc. Although the research and application on FOLEDs have made great progress, some aspects such as stability, efficiency and electrode need to be improved to achieve industrialization. In this paper, some flexible substrates and the methods to fabricate and process conductive electrode are introduced. Finally, the development trend of FOLEDs is discussed.关键词：flexible organic light-emitting devices;mechanical flexibility;flexible display;flexible substrate;conductive electrode304|481|9更新时间：2020-08-12
Device Fabrication and Physics
- 摘要：This paper researches on the influence of the three normal different material cellphone screens(LED backlight LCD, OLED, SUPER AMOLED) on adolescents circadian factor and blue light hazard factor in dark on condition that the distance of cellphones screen from pupil is 15 cm and four different color temperature. With the age, area of eye light exposure and transmittance being considerd, the calculating formula of traditional blue light hazard factor is upgraded. Circadian factor and blue light hazard factor are also calculated. It is shown that circadian factor and blue light hazard factor increase with the increase of color temperature and strong linear relation is also exist. when color temperature is between 7 425 K and 9 201 K, circadian factor ranked from high to low follows:OLED, SUPER AMOLED, LED backlight LCD. Blue light hazard factor ranked from high to low follows:LED backlight LCD, SUPER AMOLED, OLED. As a result, a relatively healthier cellphone can be chosen appropriately, according to different requirement.关键词：circadian factor;blue light hazard;cellphone screen;color temperature160|265|1更新时间：2020-08-12
- 摘要：E-field test is usually applied by one dimensional electric field sensor which is constituted of monopole antenna. For the directional character of the monopole antenna, the test result is always related to the location of the electric field sensor. In order to overcome this defect, a 3-D omnidirectional electric field sensor is designed. It is made up of monopole antenna and 3 mutually orthogonal pyramid used as reflective surface. The optimum design parameters of the 3-D pulse electric field sensor probe are determined according to the simulation of the electric field sensor on electric field under test and the influence of load impedance and the effect of antenna size characteristics of the test in the simulation software CST2012. Based on this, a 3-D pulse electric field sensor probe is made, and its major performance indicators are tested. The system provides a solution to solve the power supply problem of pulse electric field.关键词：laser power supply;LD;photovoltaic cells;‘photovoltaic eye’ZEMAX122|153|1更新时间：2020-08-12
- 摘要：A photonic crystal fiber with the cladding of circular air holes in hexagonal lattice structure and the core of circular air holes in equilateral triangle lattice structure based on cyclic-olefin copolymer is proposed, the liquid sensing characteristics of the PCF over 0.3-1.5 THz bands are investigated by finite element method. The proposed PCF demonstrates an ultrahigh sensitivity coefficient of 37.63% at 0.3 THz, and the confinement loss is low as the order 10 at frequency of 1.5 THz. The results offer reference for designing novel liquid sensors based on PCF at terahertz band.关键词：photonic crystal fiber;terahertz;sensing;sensitivity;confinement loss156|148|0更新时间：2020-08-12
Luminescence Applications and Interdisciplinary Fields
- Address：No.3888 Dong Nanhu Road, Changchun, Jilin, China Postal code：130033
- Tel：0431-86176862 Email：fgxbt@126.com
- Technical support is provided by Beijing Founder electronics co., LTD 吉ICP备11002662号-17
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0