Through the mechanochemical method,sulfamic acid(SA)is successfully introduced into UiO-66-NH_(2)to form SA@UiO-66-NH_(2).In SA@UiO-66-NH_(2),the acidic cationic sulfiliminium(—S=NH_(2)^(+))moiety formed by the bridg...Through the mechanochemical method,sulfamic acid(SA)is successfully introduced into UiO-66-NH_(2)to form SA@UiO-66-NH_(2).In SA@UiO-66-NH_(2),the acidic cationic sulfiliminium(—S=NH_(2)^(+))moiety formed by the bridging bidentate binding mode between SA and the zirconium metal center can release protons,and SA actively participates in the construction of hydrogen-bonded network,thereby accelerating the proton conduction.At 95%RH(relative humidity)and 358 K,the proton conductivity of SA@UiO-66-NH_(2)can reach 1.42×10^(-2)S·cm^(-1),which is four orders of magnitude higher than that of the parent framework UiO-66-NH_(2).Meanwhile,this high proton conductivity can be maintained for at least 90 h.展开更多
Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer...Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer,strong magnetic responses were observed in the magnetic force microscopy (MFM) measurement,which revealed that the films were independent of dopant particles and clusters. Numerical simulation on the data of atomic force microscope (AFM) and MFM measurements covering the whole microstructure validated the formation of long range magnetic order. This result excluded a variety of controversial origins of room-temperature ferromagnetism in the GaN: Mn and gave a strong evidence of our GaN: Mn as the intrinsic diluted magnetic semiconductor (DMS). The forwarded method for accurate characterization of long range magnetic order could be applied to a wide range of DMS and diluted magnetic oxide (DMO) systems.展开更多
We present an InGaAs metamorphic high electron mobility transistor （mHEMT） grown using Metalorganic Chemical Vapor Deposition （MOCVD） on an n-type silicon substrate with the introduction of an effective multi-stag...We present an InGaAs metamorphic high electron mobility transistor （mHEMT） grown using Metalorganic Chemical Vapor Deposition （MOCVD） on an n-type silicon substrate with the introduction of an effective multi-stage buffering scheme. Fabrication and performance of a high-frequency 0.3μm gate-length depletion-mode A10.s0In0.s0As/Ga0.47In0.53As mHEMT is re- ported for the first time. Using a combined optical and e-beam photolithography technology, submicron mHEMT devices on Si have been achieved. The non-alloyed ohmic contact resistance Rc was as low as 0.065 Ω-mm. A maximum transconductance up to 761 mS/ram was measured. The unity current gain cut-off frequency （fT） and the maximum oscillation frequency （fmax） were 72.8 and 74.5 GHz, respectively. This device has the highest fw yet reported for a 0.3-μm gate-length Si-based mHEMT grown using MOCVD. A high voltage gain, gm/gds, of 40.6 is observed in the device.展开更多
This review begins with an overview of the appealing properties and various applications of gold nanoparticles, and briefly summarizes recent advances in using unmodified gold nanoparticles to detect different kinds o...This review begins with an overview of the appealing properties and various applications of gold nanoparticles, and briefly summarizes recent advances in using unmodified gold nanoparticles to detect different kinds of targets including nucleic acids, proteins, metal ions and small organic molecules. The key point to the unmodified gold nanoparticle-based visual detection assay is to control dispersion and aggregation of colloidal nanoparticles by targets of interest, which usually relies on affinities between gold nanoparticles and targets. The degree of dispersion or aggregation can be visualized through the change of the solution color or the precipitation of nanoparticles from the solution. Thus, the existence of the target molecules can be trans-lated into optical signals and monitored by the naked eye conveniently. Finally, some future prospects of this research field are given.展开更多
Nonpolar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire by metal-organic chemical vapor deposition （MOCVD） under different growth pressures. The as-grown films are investigated by optical mi...Nonpolar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire by metal-organic chemical vapor deposition （MOCVD） under different growth pressures. The as-grown films are investigated by optical microscopy, high-resolution X-ray diffraction （HRXRD） and Raman scattering. As growth pressure rises from 100 mbar to 400 mbar, the surface gets rougher, and the in-plane XRD full width at half maximum （FWHM） along the c-axis [0001] increases while that along the m-axis [1100] decreases. Meanwhile, residential stresses are reduced along both the c-axis and the m-axis. The structural anisotropy feature under 400 mbar is inverted with respect to 100 mbar, and the weakened anisotropy is achieved under a moderate pressure of 200 mbar, probably due to the suppressed Ga atomic migration along the c-axis under a larger pressure. We propose that pressure can affect a-plane growth through the V/III ratio.展开更多
基金supported by the National Natural Science Foundation of China(22071019 and 21872021)the Basic Scientific Research Project of Liaoning Provincial Department of Education(LJKMZ20220968)
文摘Through the mechanochemical method,sulfamic acid(SA)is successfully introduced into UiO-66-NH_(2)to form SA@UiO-66-NH_(2).In SA@UiO-66-NH_(2),the acidic cationic sulfiliminium(—S=NH_(2)^(+))moiety formed by the bridging bidentate binding mode between SA and the zirconium metal center can release protons,and SA actively participates in the construction of hydrogen-bonded network,thereby accelerating the proton conduction.At 95%RH(relative humidity)and 358 K,the proton conductivity of SA@UiO-66-NH_(2)can reach 1.42×10^(-2)S·cm^(-1),which is four orders of magnitude higher than that of the parent framework UiO-66-NH_(2).Meanwhile,this high proton conductivity can be maintained for at least 90 h.
基金supported by the National Natural Science Foundation of China (Grant Nos.60577030,60776041,60876035)the National Key Basic Research Special Foundation of China (Grant Nos.TG2007CB307004,2006CB921607)
文摘Room-temperature ferromagnetism with a Curie temperature higher than 380 K was studied in GaN: Mn thin films grown by metal-organic chemical vapor deposition. By etching artificial microstructures on the GaN: Mn layer,strong magnetic responses were observed in the magnetic force microscopy (MFM) measurement,which revealed that the films were independent of dopant particles and clusters. Numerical simulation on the data of atomic force microscope (AFM) and MFM measurements covering the whole microstructure validated the formation of long range magnetic order. This result excluded a variety of controversial origins of room-temperature ferromagnetism in the GaN: Mn and gave a strong evidence of our GaN: Mn as the intrinsic diluted magnetic semiconductor (DMS). The forwarded method for accurate characterization of long range magnetic order could be applied to a wide range of DMS and diluted magnetic oxide (DMO) systems.
基金supported by the CERG(Grant No. 615506) from the Research Grants Council of Hong Kong and Intel Corporation
文摘We present an InGaAs metamorphic high electron mobility transistor （mHEMT） grown using Metalorganic Chemical Vapor Deposition （MOCVD） on an n-type silicon substrate with the introduction of an effective multi-stage buffering scheme. Fabrication and performance of a high-frequency 0.3μm gate-length depletion-mode A10.s0In0.s0As/Ga0.47In0.53As mHEMT is re- ported for the first time. Using a combined optical and e-beam photolithography technology, submicron mHEMT devices on Si have been achieved. The non-alloyed ohmic contact resistance Rc was as low as 0.065 Ω-mm. A maximum transconductance up to 761 mS/ram was measured. The unity current gain cut-off frequency （fT） and the maximum oscillation frequency （fmax） were 72.8 and 74.5 GHz, respectively. This device has the highest fw yet reported for a 0.3-μm gate-length Si-based mHEMT grown using MOCVD. A high voltage gain, gm/gds, of 40.6 is observed in the device.
基金supported by the Ministry of Science and Technology(Grant Nos. 2009CB930000 and 2011CB933201)the National Natural Science Foundation of China (Grant Nos. 20890020, 21025520 and 90813032)+2 种基金the Chinese Academy of Sciences (Grant No. KJCX2-YW-M15)the Fundamental Research Funds for the Central Universities (Grant No.CDJXS10232211)the Ministry of Human Resources and Social Security of China
文摘This review begins with an overview of the appealing properties and various applications of gold nanoparticles, and briefly summarizes recent advances in using unmodified gold nanoparticles to detect different kinds of targets including nucleic acids, proteins, metal ions and small organic molecules. The key point to the unmodified gold nanoparticle-based visual detection assay is to control dispersion and aggregation of colloidal nanoparticles by targets of interest, which usually relies on affinities between gold nanoparticles and targets. The degree of dispersion or aggregation can be visualized through the change of the solution color or the precipitation of nanoparticles from the solution. Thus, the existence of the target molecules can be trans-lated into optical signals and monitored by the naked eye conveniently. Finally, some future prospects of this research field are given.
基金supported by the National Natural Science Foundation of China (Grant Nos. 60890192 and 50872146)
文摘Nonpolar a-plane （1120） GaN films have been grown on r-plane （1102） sapphire by metal-organic chemical vapor deposition （MOCVD） under different growth pressures. The as-grown films are investigated by optical microscopy, high-resolution X-ray diffraction （HRXRD） and Raman scattering. As growth pressure rises from 100 mbar to 400 mbar, the surface gets rougher, and the in-plane XRD full width at half maximum （FWHM） along the c-axis [0001] increases while that along the m-axis [1100] decreases. Meanwhile, residential stresses are reduced along both the c-axis and the m-axis. The structural anisotropy feature under 400 mbar is inverted with respect to 100 mbar, and the weakened anisotropy is achieved under a moderate pressure of 200 mbar, probably due to the suppressed Ga atomic migration along the c-axis under a larger pressure. We propose that pressure can affect a-plane growth through the V/III ratio.
