A new method has been developed for fabrication of copper micro-pattern by selective chemical copper deposition based on photolithographed (3-mercaptopropyl)-trimethoxysilane (MPTS) self-assembly monolayers (SAMs). A...A new method has been developed for fabrication of copper micro-pattern by selective chemical copper deposition based on photolithographed (3-mercaptopropyl)-trimethoxysilane (MPTS) self-assembly monolayers (SAMs). As confirmed by scanning electron microscopy (SEM), Cu closely replicated the mask features. The present approach makes this technic to be cheap and may be applicable to assembly of microelectronic circuits.展开更多
A pre-ohmic micro-patterned recess process,is utilized to fabricate Ti/Al/Ti/TiN ohmic contact to an ultrathin-barrier(UTB)AlGaN/GaN heterostructure,featuring a significantly reduced ohmic contact resistivity of 0.56...A pre-ohmic micro-patterned recess process,is utilized to fabricate Ti/Al/Ti/TiN ohmic contact to an ultrathin-barrier(UTB)AlGaN/GaN heterostructure,featuring a significantly reduced ohmic contact resistivity of 0.56Ω·mm at an alloy temperature of 550℃.The sheet resistances increase with the temperature following a power law with the index of +2.58,while the specific contact resistivity decreases with the temperature.The contact mechanism can be well described by thermionic field emission(TFE).The extracted Schottky barrier height and electron concentration are 0.31 eV and 5.52×10^(18) cm^(−3),which suggests an intimate contact between ohmic metal and the UTB-AlGaN as well as GaN buffer.A good correlation between ohmic transfer length and the micro-pattern size is revealed,though in-depth investigation is needed.A preliminary CMOS-process-compatible metal-insulator-semiconductor high-mobility transistor(MIS-HEMT)was fabricated with the proposed Au-free ohmic contact technique.展开更多
Angular color uniformity(ACU)is a key factor used to evaluate the light quality of white-light emitting diodes(LEDs).In this study,a novel double remote micro-patterned phosphor film(double RMPP film)was used to enhan...Angular color uniformity(ACU)is a key factor used to evaluate the light quality of white-light emitting diodes(LEDs).In this study,a novel double remote micro-patterned phosphor film(double RMPP film)was used to enhance the ACU of a remote phosphor(RP)down-light lamp.A conventional RP film and remote phosphor film with single micro-patterned film(single RMPP film)also were examined for comparison.The angular correlated color temperature(CCT)distributions and the optical performance of the films were experimentally measured.The measurement results showed that double RMPP film configuration exhibited better color uniformity with a CCT deviation of only 441 K,compared with 556 K for the single RMPP film configuration and 1390 K for the RP film configuration.A simulation based on FDTD and ray tracing combined method also confirmed the ACU improvement.In addition,compared with the conventional RP film,the luminous efficiency of single and double RMPP film configurations was increased by 6.68% and 4.69%,respectively,at a driving current of 350 mA.The enhancement of the ACU and luminous efficiency are due to the scattering and mixing effect of the micropatterned film.Moreover,the double RMPP film configuration had better CCT stability at different currents than the other two configurations.The results demonstrated the effectiveness and superiority of double RMPP film in white LED applications.展开更多
The requirement of a large number of electronic channels poses a big challenge to the further applications of Micro-pattern Gas Detectors （MPGDs）. By using the redundancy that at least two neighboring strips record ...The requirement of a large number of electronic channels poses a big challenge to the further applications of Micro-pattern Gas Detectors （MPGDs）. By using the redundancy that at least two neighboring strips record the signal of a particle, a novel method of encoded multiplexing readout for MPGDs is presented in this paper. The method offers a feasible and easily-extensible way of encoding and decoding, and can significantly reduce the number of readout channels. A verification test was carried out on a 5 cm×5 cm Thick Gas Electron Multiplier （THGEM） detector using a 8 keV Cu X-ray source with 100um slit, where 166 strips were read out by 21 encoded readout channels. The test results show good linearity in its position response, and the spatial resolution root-mean-square （RMS） of the test system is about 260um. This method has potential to build large area detectors and can be easily adapted to other detectors similar to MPGDs.展开更多
In this study,a micro-patterned hydroxyapatite/silk fibroin(HA-SF)coating was firstly fabricated on the surface of Mg-Zn-Y-Nd-Zr alloy by template-assisted electrospraying technique coupling with spin coating techniqu...In this study,a micro-patterned hydroxyapatite/silk fibroin(HA-SF)coating was firstly fabricated on the surface of Mg-Zn-Y-Nd-Zr alloy by template-assisted electrospraying technique coupling with spin coating technique.Two types of micro-patterns were achieved with high contour accuracy,namely HA SF(line-pattern)and HA-SF(dot-pattern).The microstructure,composition,surface wettability and corrosion behaviors of the coatings were investigated by SEM,EDS,FTIR,XRD,water contact angle and potentiodynamic polarization test.The results revealed the hydrophilic nature of coatings and two orders of magnitude reduction of corrosion density(icorr)as compared with that of the substrate.All the micro-patterned surfaces promoted the attachment of MC3T3-E1 cells with visible filopodia after 1 d incubation.In addition,coatings with line pattern exhibited the superior guidance to cell migration as compared to dot pattern,and the preference of cell attachment in the convex zone was observed.In summary,the obtained micro-patterned HA-SF coatings possessed the remarkably improvement of anticorrosion ability and good efficacy in guidance of cell attachment and alignment,which can serve as a promising strategy for cellular response modulation at the interface of magnesium-based implants and bone.展开更多
A scalable readout system （SRS） is designed to provide a general solution for different micro-pattern gas detectors in various applications. The system mainly consists of three kinds of modules： the ASIC card, the ...A scalable readout system （SRS） is designed to provide a general solution for different micro-pattern gas detectors in various applications. The system mainly consists of three kinds of modules： the ASIC card, the adapter card and the front-end card （FEC）. The ASIC cards, mounted with particular ASIC chips, are designed for receiving detector signals. The adapter card is in charge of digitizing the output signals from several ASIC cards. The FEC, edged-mounted with the adapter, has field-programmable gate array （FPGA）-based reconfigurable logic and I/O interfaces, allowing users to choose different ASIC cards and adapters for different experiments, which expands the system to various applications. The FEC transfers data through Gigabit Ethernet protocol realized by a TCP processor （SiTCP） IP core in FPGA. By assembling a flexible number of FECs in parallel through Gigabit Ethernet, the readout system can be tailored to specific sizes to adapt to the experiment scales and readout requirements. In this paper, two kinds of multi-channel ASIC chip, VA140 and AGET, are applied to verify the scalability of this SRS architecture. Based on this VA140 or AGET SRS, one FEC covers 8 ASIC （VA140） cards handling 512 detector channels, or 4 ASIC （AGET） cards handling 256 detector channels, respectively. More FECs can be assembled in crates to handle thousands of detector channels.展开更多
The two-dimensional interpolating readout, a new readout concept based on resistive anode structure, was studied for the micro-pattern gaseous detector. Within its high spatial resolution, the interpolating resistive ...The two-dimensional interpolating readout, a new readout concept based on resistive anode structure, was studied for the micro-pattern gaseous detector. Within its high spatial resolution, the interpolating resistive readout structure leads to an enormous reduction of electronic channels compared with pure pixel devices, and also makes the detector more reliable and robust, which is attributed to its resistive anode relieving discharge. A GEM （gaseous electron multiplier） detector with 2D interpolating resistive readout structure was set up and the performance of the detector was studied with ^55Fe 5.9 keV X-ray. The detector worked stably at the gain up to 3.5 × 104 without any discharge. An energy resolution of about 19%, and a spatial resolution of about 219 μm （FWHM） were reached, and good imaging performance was also obtained.展开更多
A liquid crystal Pancharatnam–Berry（PB） axilens is proposed and fabricated via a digital micro-mirrordevice-based photo-patterning system. The polarization-dependent device behaves as an axilens for a lefthanded ci...A liquid crystal Pancharatnam–Berry（PB） axilens is proposed and fabricated via a digital micro-mirrordevice-based photo-patterning system. The polarization-dependent device behaves as an axilens for a lefthanded circularly polarized incident beam, for which an optical ring is focused with a long focal depth in the transverse direction at the output, and an anti-axilens for a right-handed circularly polarized incident beam,for which an optical ring gradually expands at the output. The modification of the size and the sharpness of the diffracted ring beam is demonstrated by encoding a positive（negative） PB lens term into the director expression of a PB（anti-）axicon.展开更多
The wedge strip anode （WSA） has been widely used in 2-D positiomsensitive detectors. A circular WSA with an effective diameter of 52 mm is successfully coupled to a tripe gas electron multiplier （GEM） detector thr...The wedge strip anode （WSA） has been widely used in 2-D positiomsensitive detectors. A circular WSA with an effective diameter of 52 mm is successfully coupled to a tripe gas electron multiplier （GEM） detector through a simple resistive layer. A spatial resolution of 440 μm （FWHM） is achieved for a 10 kVp X-ray using 1 atm Ar：CO2=70：30 gas. The simple electronics of only three channels makes it very useful in applications strongly requiring simple interface design, e.g. sealed tubes and high pressure detectors.展开更多
基金This work was supported by the National Natural Science Foundation of the Peoples Republic of China (No. 69890220).
文摘A new method has been developed for fabrication of copper micro-pattern by selective chemical copper deposition based on photolithographed (3-mercaptopropyl)-trimethoxysilane (MPTS) self-assembly monolayers (SAMs). As confirmed by scanning electron microscopy (SEM), Cu closely replicated the mask features. The present approach makes this technic to be cheap and may be applicable to assembly of microelectronic circuits.
基金supported by National Natural Science Foundation of China under Grant 61822407,Grant 62074161,and Grant 11634002in part by the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(CAS)under Grant QYZDB-SSW-JSC012+3 种基金in part by the National Key Research and Development Program of China under Grant 2016YFB0400105 and Grant 2017YFB0403000in part by the Youth Innovation Promotion Association of CASin part by the University of Chinese Academy of Sciencesand in part by the Opening Project of Key Laboratory of Microelectronic Devices&Integrated Technology,Institute of Microelectronics,CAS.
文摘A pre-ohmic micro-patterned recess process,is utilized to fabricate Ti/Al/Ti/TiN ohmic contact to an ultrathin-barrier(UTB)AlGaN/GaN heterostructure,featuring a significantly reduced ohmic contact resistivity of 0.56Ω·mm at an alloy temperature of 550℃.The sheet resistances increase with the temperature following a power law with the index of +2.58,while the specific contact resistivity decreases with the temperature.The contact mechanism can be well described by thermionic field emission(TFE).The extracted Schottky barrier height and electron concentration are 0.31 eV and 5.52×10^(18) cm^(−3),which suggests an intimate contact between ohmic metal and the UTB-AlGaN as well as GaN buffer.A good correlation between ohmic transfer length and the micro-pattern size is revealed,though in-depth investigation is needed.A preliminary CMOS-process-compatible metal-insulator-semiconductor high-mobility transistor(MIS-HEMT)was fabricated with the proposed Au-free ohmic contact technique.
基金National Natural Science Foundation of China(NSFC)(U1401249,51405161)Guandong Natural Science Foundation(2014A030312017)+1 种基金China Postdoctoral Science Foundation(2015T80904)Science&Technology Program of Guangdong Province(2014B010121002)
文摘Angular color uniformity(ACU)is a key factor used to evaluate the light quality of white-light emitting diodes(LEDs).In this study,a novel double remote micro-patterned phosphor film(double RMPP film)was used to enhance the ACU of a remote phosphor(RP)down-light lamp.A conventional RP film and remote phosphor film with single micro-patterned film(single RMPP film)also were examined for comparison.The angular correlated color temperature(CCT)distributions and the optical performance of the films were experimentally measured.The measurement results showed that double RMPP film configuration exhibited better color uniformity with a CCT deviation of only 441 K,compared with 556 K for the single RMPP film configuration and 1390 K for the RP film configuration.A simulation based on FDTD and ray tracing combined method also confirmed the ACU improvement.In addition,compared with the conventional RP film,the luminous efficiency of single and double RMPP film configurations was increased by 6.68% and 4.69%,respectively,at a driving current of 350 mA.The enhancement of the ACU and luminous efficiency are due to the scattering and mixing effect of the micropatterned film.Moreover,the double RMPP film configuration had better CCT stability at different currents than the other two configurations.The results demonstrated the effectiveness and superiority of double RMPP film in white LED applications.
基金Supported by National Natural Science Foundation of China(11222552,11265003)
文摘The requirement of a large number of electronic channels poses a big challenge to the further applications of Micro-pattern Gas Detectors （MPGDs）. By using the redundancy that at least two neighboring strips record the signal of a particle, a novel method of encoded multiplexing readout for MPGDs is presented in this paper. The method offers a feasible and easily-extensible way of encoding and decoding, and can significantly reduce the number of readout channels. A verification test was carried out on a 5 cm×5 cm Thick Gas Electron Multiplier （THGEM） detector using a 8 keV Cu X-ray source with 100um slit, where 166 strips were read out by 21 encoded readout channels. The test results show good linearity in its position response, and the spatial resolution root-mean-square （RMS） of the test system is about 260um. This method has potential to build large area detectors and can be easily adapted to other detectors similar to MPGDs.
基金supported by the National Natural Science Foundation of China(Grant Nos.51601169,51671175 and 51701184)the National Key Research and Development Program of China(2018YFC1106703)the Key Projects of the Joint Fund of the National Natural Science Foundation of China(U1804251)。
文摘In this study,a micro-patterned hydroxyapatite/silk fibroin(HA-SF)coating was firstly fabricated on the surface of Mg-Zn-Y-Nd-Zr alloy by template-assisted electrospraying technique coupling with spin coating technique.Two types of micro-patterns were achieved with high contour accuracy,namely HA SF(line-pattern)and HA-SF(dot-pattern).The microstructure,composition,surface wettability and corrosion behaviors of the coatings were investigated by SEM,EDS,FTIR,XRD,water contact angle and potentiodynamic polarization test.The results revealed the hydrophilic nature of coatings and two orders of magnitude reduction of corrosion density(icorr)as compared with that of the substrate.All the micro-patterned surfaces promoted the attachment of MC3T3-E1 cells with visible filopodia after 1 d incubation.In addition,coatings with line pattern exhibited the superior guidance to cell migration as compared to dot pattern,and the preference of cell attachment in the convex zone was observed.In summary,the obtained micro-patterned HA-SF coatings possessed the remarkably improvement of anticorrosion ability and good efficacy in guidance of cell attachment and alignment,which can serve as a promising strategy for cellular response modulation at the interface of magnesium-based implants and bone.
基金Supported by National Natural Science Foundation of China(11222552)
文摘A scalable readout system （SRS） is designed to provide a general solution for different micro-pattern gas detectors in various applications. The system mainly consists of three kinds of modules： the ASIC card, the adapter card and the front-end card （FEC）. The ASIC cards, mounted with particular ASIC chips, are designed for receiving detector signals. The adapter card is in charge of digitizing the output signals from several ASIC cards. The FEC, edged-mounted with the adapter, has field-programmable gate array （FPGA）-based reconfigurable logic and I/O interfaces, allowing users to choose different ASIC cards and adapters for different experiments, which expands the system to various applications. The FEC transfers data through Gigabit Ethernet protocol realized by a TCP processor （SiTCP） IP core in FPGA. By assembling a flexible number of FECs in parallel through Gigabit Ethernet, the readout system can be tailored to specific sizes to adapt to the experiment scales and readout requirements. In this paper, two kinds of multi-channel ASIC chip, VA140 and AGET, are applied to verify the scalability of this SRS architecture. Based on this VA140 or AGET SRS, one FEC covers 8 ASIC （VA140） cards handling 512 detector channels, or 4 ASIC （AGET） cards handling 256 detector channels, respectively. More FECs can be assembled in crates to handle thousands of detector channels.
文摘The two-dimensional interpolating readout, a new readout concept based on resistive anode structure, was studied for the micro-pattern gaseous detector. Within its high spatial resolution, the interpolating resistive readout structure leads to an enormous reduction of electronic channels compared with pure pixel devices, and also makes the detector more reliable and robust, which is attributed to its resistive anode relieving discharge. A GEM （gaseous electron multiplier） detector with 2D interpolating resistive readout structure was set up and the performance of the detector was studied with ^55Fe 5.9 keV X-ray. The detector worked stably at the gain up to 3.5 × 104 without any discharge. An energy resolution of about 19%, and a spatial resolution of about 219 μm （FWHM） were reached, and good imaging performance was also obtained.
基金sponsored by the National Natural Science Foundation of China(NSFC)(Nos.61435008,61705067,and 61575063)the Shanghai Pujiang Program(No.16PJ1402200)+1 种基金the Shanghai Rising-Star Program(No.17QA1401100)the State Key Laboratory on Advanced Displays and Optoelectronics Technologies,ECE Department,HKUST,Hong Kong
文摘A liquid crystal Pancharatnam–Berry（PB） axilens is proposed and fabricated via a digital micro-mirrordevice-based photo-patterning system. The polarization-dependent device behaves as an axilens for a lefthanded circularly polarized incident beam, for which an optical ring is focused with a long focal depth in the transverse direction at the output, and an anti-axilens for a right-handed circularly polarized incident beam,for which an optical ring gradually expands at the output. The modification of the size and the sharpness of the diffracted ring beam is demonstrated by encoding a positive（negative） PB lens term into the director expression of a PB（anti-）axicon.
基金Supported by National Natural Science Foundation of China (10735020, 11075026)
文摘The wedge strip anode （WSA） has been widely used in 2-D positiomsensitive detectors. A circular WSA with an effective diameter of 52 mm is successfully coupled to a tripe gas electron multiplier （GEM） detector through a simple resistive layer. A spatial resolution of 440 μm （FWHM） is achieved for a 10 kVp X-ray using 1 atm Ar：CO2=70：30 gas. The simple electronics of only three channels makes it very useful in applications strongly requiring simple interface design, e.g. sealed tubes and high pressure detectors.
