This paper proposes a new filter biquad circuit, which utilizes three Current Differencing Buffered Amplifiers (CDBA), two capacitors and five resistors, and operates in the trans-resistance mode. This multi-input and...This paper proposes a new filter biquad circuit, which utilizes three Current Differencing Buffered Amplifiers (CDBA), two capacitors and five resistors, and operates in the trans-resistance mode. This multi-input and single-output multifunction filter uses only grounded capacitors. All the employed resistors are either grounded or virtually grounded, which is an important parameter for its implementation as an integrated circuit. The circuit enjoys independent tunability of angular frequency and bandwidth. The 0.5 μm technology process parameters have been utilized to test and verify the performance characteristics of the circuit using PSPICE. The non-ideal analysis and sensitivity analysis, transient response, Monte-Carlo analysis and calculations of total harmonic distortion have also been shown.展开更多
The performance of an organic photovoltaic （OPV） cell based on copper phthatocyanine CuPc/C60 with a tris- （8-hydroxyquinolinato） aluminum （Alq3） buffer layer has been investigated. It was found that the power c...The performance of an organic photovoltaic （OPV） cell based on copper phthatocyanine CuPc/C60 with a tris- （8-hydroxyquinolinato） aluminum （Alq3） buffer layer has been investigated. It was found that the power conversion efficiency of the device was 1.51% under illumination with an intensity of 100 mW/cm^2, which was limited by a squareroot dependence of the photocurrent on voltage. The photocurrent optical power density characteristics showed that the OPV cell had a significant space-charge limited photocurrent with a varied saturation voltage and a three quarters power dependence on optical power density. Also, the absorption spectrum was measured by a spectrophotometer, and the results showed that the additional Alq3 layer has a minor effect on photocurrent generation.展开更多
Ba0.6Sr0.4TiO3 （BST） thin films with and without HfO 2 buffer layer were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Dependences of HfO 2 thickness on the dielectric property and leakage curre...Ba0.6Sr0.4TiO3 （BST） thin films with and without HfO 2 buffer layer were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Dependences of HfO 2 thickness on the dielectric property and leakage current of BST thin films were focused. The dielectric constant of BST thin films increased and then decreased with the increase of HfO 2 thickness, while the dielectric relaxation was gradually improved. The loss tangent and leakage current under positive bias decreased with the HfO 2 thickness increasing. The leakage current analysis based on the Schottky emission indicated an improvement of the BST/Pt interface with HfO 2 buffer layer. The loss tangent, tunability and figure of merit of optimized HfO 2 buffered BST thin film achieved 0.009 8, 21.91% （E max = 200 kV/cm）, 22.40 at 10 6 Hz, respectively.展开更多
文摘This paper proposes a new filter biquad circuit, which utilizes three Current Differencing Buffered Amplifiers (CDBA), two capacitors and five resistors, and operates in the trans-resistance mode. This multi-input and single-output multifunction filter uses only grounded capacitors. All the employed resistors are either grounded or virtually grounded, which is an important parameter for its implementation as an integrated circuit. The circuit enjoys independent tunability of angular frequency and bandwidth. The 0.5 μm technology process parameters have been utilized to test and verify the performance characteristics of the circuit using PSPICE. The non-ideal analysis and sensitivity analysis, transient response, Monte-Carlo analysis and calculations of total harmonic distortion have also been shown.
基金Project supported by the National Natural Science Foundation of China (NSFC) (Grant Nos. 60736005 and 60425101-1)the Foundation for Innovative Research Groups of the NSFC (Grant No. 60721001),Provincial Project (Grant No. 9140A02060609DZ0208)+1 种基金Program for New Century Excellent Talents in University (Grant No. NCET-06-0812),SRF for ROCS,SEM (Grant No. GGRYJJ08-05)Young Excellent Project of Sichuan Province (Grant No. 09ZQ026-074)
文摘The performance of an organic photovoltaic （OPV） cell based on copper phthatocyanine CuPc/C60 with a tris- （8-hydroxyquinolinato） aluminum （Alq3） buffer layer has been investigated. It was found that the power conversion efficiency of the device was 1.51% under illumination with an intensity of 100 mW/cm^2, which was limited by a squareroot dependence of the photocurrent on voltage. The photocurrent optical power density characteristics showed that the OPV cell had a significant space-charge limited photocurrent with a varied saturation voltage and a three quarters power dependence on optical power density. Also, the absorption spectrum was measured by a spectrophotometer, and the results showed that the additional Alq3 layer has a minor effect on photocurrent generation.
基金Project supported by the Foundation of the Education Commission of Shanghai Municipality (Grant Nos.07ZZ14, 08SG41)the National Natural Science Foundation of China (Grant No.50711130241)the Shanghai Rising Star Program (GrantNo.08QH14008)
文摘Ba0.6Sr0.4TiO3 （BST） thin films with and without HfO 2 buffer layer were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. Dependences of HfO 2 thickness on the dielectric property and leakage current of BST thin films were focused. The dielectric constant of BST thin films increased and then decreased with the increase of HfO 2 thickness, while the dielectric relaxation was gradually improved. The loss tangent and leakage current under positive bias decreased with the HfO 2 thickness increasing. The leakage current analysis based on the Schottky emission indicated an improvement of the BST/Pt interface with HfO 2 buffer layer. The loss tangent, tunability and figure of merit of optimized HfO 2 buffered BST thin film achieved 0.009 8, 21.91% （E max = 200 kV/cm）, 22.40 at 10 6 Hz, respectively.
