AlGaAs/GaAs multi-quantum well (MQW) was prepared by molecular beam epitaxy(MBE) with growth-interrupted heterointerface (GIH) method and continuous growth (CG) method, respectively. The microstructures of the MQWs we...AlGaAs/GaAs multi-quantum well (MQW) was prepared by molecular beam epitaxy(MBE) with growth-interrupted heterointerface (GIH) method and continuous growth (CG) method, respectively. The microstructures of the MQWs were characterized by double-crystal X-ray rocking curve (DCRC) and atomic force microscopy (AFM), and the photoluminescence (PL) properties of the MQWs were also studied. The MQWs grown with GIH method show that higher order satellite peaks of Pendell?sung fringes are observed in DCRC, the roughness of surface is much reduced in AFM, and the full width at half maximum (FWHM) of exciton line is much narrower in PL. The results indicate that the GIH method reduces the monolayer growth step density at the heterointerface due to the migration of surface atoms for a few minutes growth interruption, and substantially improves the quality of AlGaAs/GaAs MQWs.展开更多
We report a type-Ⅱ InAs/GaSb superlattice three-color infrared detector for mid-wave （MW）, long-wave （LW）, and very long-wave （VLW） detections. The detector structure consists of three contacts of NIPIN archite...We report a type-Ⅱ InAs/GaSb superlattice three-color infrared detector for mid-wave （MW）, long-wave （LW）, and very long-wave （VLW） detections. The detector structure consists of three contacts of NIPIN architecture for MW and LW detections, and hetero-junction NIP architecture for VLW detection. It is found that the spectral crosstalks can be significantly reduced by controlling the minority carriers transport via doping beryllium in the two active regions of NIPIN section. The crosstalk detection at MW, LW, and VLW signals are achieved by selecting the bias voltages on the device. At 77K, the cutoff wavelengths of the three-color detection are 5.3μm （at OmV）, 141μm （at 300mV） and 19μm （at -20mV） with the detectivities of 4.6xlO11 cm.Hzl/ZW-1, 2.3×10^10 cm.Hzl/2W-1, and 1.0×10^10cm.Hzl/2W-1 for MW, LW and VLW. The crosstalks of the MW channel, LW channel, and VLW channel are almost 0, 0.25, and 0.6, respectively.展开更多
To investigate the upconversion emission, this paper synthesizes Tm^3＋ and Yb^3＋ codoped Y2O3 nanoparticles, and then coats them with TiO2 shells for different coating times. The spectral results of TiO2 coated nano...To investigate the upconversion emission, this paper synthesizes Tm^3＋ and Yb^3＋ codoped Y2O3 nanoparticles, and then coats them with TiO2 shells for different coating times. The spectral results of TiO2 coated nanoparticles indicate that upconversion emission intensities have respectively been enhanced 3.2, 5.4, and 2.2 times for coating times of 30, 60 and 90 min at an excitation power density of 3.21× 10^2 W. cm^-2, in comparison with the emission intensity of non-coated nanoparticles. Therefore it can be concluded that the intense upconversion emission of Y2O3：Tm^3＋, Yb^3＋ nanoparticles can be achieved by coating the particle surfaces with a shell of specific thickness.展开更多
An Si(001)/SiO2/Ti/Pt/Fe/Cu multilayer was prepared by direct-current magnetic sputtering system. The phase composition of the film was characterized by X-ray diffractometry(XRD), and the microstructure was observed b...An Si(001)/SiO2/Ti/Pt/Fe/Cu multilayer was prepared by direct-current magnetic sputtering system. The phase composition of the film was characterized by X-ray diffractometry(XRD), and the microstructure was observed by scanning electronic microscopy(SEM). Through the film annealed in magnetic field perpendicular to the surface of the film, FCC FePt film with (001) texture was obtained. And the density of the particle in the film annealed without magnetic field is very small compared with that in the film annealed with magnetic field. And the effect of magnetic field annealing on the microstructure of Fe/Pt film and the segregation of FCC FePt phase were also discussed.展开更多
Dislocation behaviors are analyzed in AlGaN/GaN multiple-quantum-well films grown with different strain-modified interlayers.In the case of multiple-quantum-well layers grown on a GaN buffer layer without the interlay...Dislocation behaviors are analyzed in AlGaN/GaN multiple-quantum-well films grown with different strain-modified interlayers.In the case of multiple-quantum-well layers grown on a GaN buffer layer without the interlayer,many threading dislocations interact and annihilate within about 100 nm below the multiple quantum well layer.For multiple-quantum-well layers grown with the AlGaN interlayer,misfit dislocations between the GaN buffer layer and the AlGaN interlayer enter multiple-quantum-well layers and result in an increase of threading dislocation density.Besides misfit dislocations,the edge-type dislocation is another dislocation origin attributed to the dissociation of Shockley partials bounding the stacking fault in AlN/GaN superlattices below the interlayer interface.展开更多
文摘AlGaAs/GaAs multi-quantum well (MQW) was prepared by molecular beam epitaxy(MBE) with growth-interrupted heterointerface (GIH) method and continuous growth (CG) method, respectively. The microstructures of the MQWs were characterized by double-crystal X-ray rocking curve (DCRC) and atomic force microscopy (AFM), and the photoluminescence (PL) properties of the MQWs were also studied. The MQWs grown with GIH method show that higher order satellite peaks of Pendell?sung fringes are observed in DCRC, the roughness of surface is much reduced in AFM, and the full width at half maximum (FWHM) of exciton line is much narrower in PL. The results indicate that the GIH method reduces the monolayer growth step density at the heterointerface due to the migration of surface atoms for a few minutes growth interruption, and substantially improves the quality of AlGaAs/GaAs MQWs.
基金Supported by the National Basic Research Program of China under Grant Nos 2014CB643903,2013CB932904,2012CB932701 and 2011CB922201the National Special Funds for the Development of Major Research Equipment and Instruments of China under Grant No 2012YQ140005+7 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB01010200the China Postdoctoral Science Foundation-funded Project under Grant No 2014M561029the Program for New Century Excellent Talents in University under Grant No NCET-10-0066the National High-Technology Research and Development Program of China under Grant No 2013AA031502the Science and Technology Innovation Project of Harbin City under Grant No2011RFLXG006the National Natural Science Foundation of China under Grant Nos 61274013,U1037602,61306013,51202046,and 61290303the China Postdoctoral Science Foundation under Grant Nos 2012M510144 and 2013T60366the Fundamental Research Funds for the Central Universities under Grant Nos HIT.NSRIF.2013006 and HIT.BRETIII.201403
文摘We report a type-Ⅱ InAs/GaSb superlattice three-color infrared detector for mid-wave （MW）, long-wave （LW）, and very long-wave （VLW） detections. The detector structure consists of three contacts of NIPIN architecture for MW and LW detections, and hetero-junction NIP architecture for VLW detection. It is found that the spectral crosstalks can be significantly reduced by controlling the minority carriers transport via doping beryllium in the two active regions of NIPIN section. The crosstalk detection at MW, LW, and VLW signals are achieved by selecting the bias voltages on the device. At 77K, the cutoff wavelengths of the three-color detection are 5.3μm （at OmV）, 141μm （at 300mV） and 19μm （at -20mV） with the detectivities of 4.6xlO11 cm.Hzl/ZW-1, 2.3×10^10 cm.Hzl/2W-1, and 1.0×10^10cm.Hzl/2W-1 for MW, LW and VLW. The crosstalks of the MW channel, LW channel, and VLW channel are almost 0, 0.25, and 0.6, respectively.
文摘To investigate the upconversion emission, this paper synthesizes Tm^3＋ and Yb^3＋ codoped Y2O3 nanoparticles, and then coats them with TiO2 shells for different coating times. The spectral results of TiO2 coated nanoparticles indicate that upconversion emission intensities have respectively been enhanced 3.2, 5.4, and 2.2 times for coating times of 30, 60 and 90 min at an excitation power density of 3.21× 10^2 W. cm^-2, in comparison with the emission intensity of non-coated nanoparticles. Therefore it can be concluded that the intense upconversion emission of Y2O3：Tm^3＋, Yb^3＋ nanoparticles can be achieved by coating the particle surfaces with a shell of specific thickness.
文摘An Si(001)/SiO2/Ti/Pt/Fe/Cu multilayer was prepared by direct-current magnetic sputtering system. The phase composition of the film was characterized by X-ray diffractometry(XRD), and the microstructure was observed by scanning electronic microscopy(SEM). Through the film annealed in magnetic field perpendicular to the surface of the film, FCC FePt film with (001) texture was obtained. And the density of the particle in the film annealed without magnetic field is very small compared with that in the film annealed with magnetic field. And the effect of magnetic field annealing on the microstructure of Fe/Pt film and the segregation of FCC FePt phase were also discussed.
基金Supported by the Natural Science Foundation of Heilongjiang Province under Grant No F2007-1the Open Experimentation Program of Beijing Institute of Technology(BJUT-GTS-200904).
文摘Dislocation behaviors are analyzed in AlGaN/GaN multiple-quantum-well films grown with different strain-modified interlayers.In the case of multiple-quantum-well layers grown on a GaN buffer layer without the interlayer,many threading dislocations interact and annihilate within about 100 nm below the multiple quantum well layer.For multiple-quantum-well layers grown with the AlGaN interlayer,misfit dislocations between the GaN buffer layer and the AlGaN interlayer enter multiple-quantum-well layers and result in an increase of threading dislocation density.Besides misfit dislocations,the edge-type dislocation is another dislocation origin attributed to the dissociation of Shockley partials bounding the stacking fault in AlN/GaN superlattices below the interlayer interface.
