(A) XRD pattern of the NiFe2O4 particles prepared by microwave assisted route; and (B) SEM micrograph of NiFe2O4.
(a) SEM micrographs of chitosan; (b) NiFe2O4/chitosan; and (c) HRP/NiFe2O4/chitosan.
Electrochemical impedance spectra of: (a) Bare GCE; (b) chitosan; (c) NiFe2O4/chitosan; (d) HRP/NiFe2O4/chitosan; and (e) HRP/chitosan electrodes in 10 mM PBS solutiıon containing [Fe(CN)6]3−/4− (5 mM) (pH=8.5).
CVs of: (a) chitosan; (b) NiFe2O4/chitosan; and (c) HRP/NiFe2O4/chitosan electrodes in 10 mM PBS solution containing [Fe(CN)6]3−/4− (10 mM) at 10-100 mVs−1 (from inner to outer).
CVs of the HRP/CS/GPTMS-modified electrode in 0.02 moll−1 PBS (pH=8.0) containing [Fe(CN)6]3-/4- (10 mM) at a scan rate of 50 mVs-1 (a) without H2O2; and (b) with 5 mmoll−1 H2O2.
(a) Effect of HRP concentration on the enzyme electrode in 10 mM PBS solution (pH=8.0); (b) Effect of the applied potential on the amperometric response of the enzyme electrode to 12 mM H2O2 in 10 mM PBS solution (pH=8.0); (c) Effect of pH on the amperometric response of 12 mM H2O2 in 10 mM PBS solution at an applied potential of -100 mV vs. Ag/AgCl; and (d) Effect of temperature on the amperometric response of 12 mM H2O2 in 10 mM PBS solution (pH=8.0) at an applied potential of -100 mV vs. Ag/AgCl.
Typical current-time responses obtained with enzyme electrode at an applied potential -100 mV to successive analyte addition in a stirred 10 mM PBS (pH=8.0). The calibration curve corresponding to the current response of different concentration of H2O2 is given as inset.
In order to optimize carrier capture and the spectral response of the quantum dot infrared detector independently, the quantum dot infrared photodetector can be divided in an injector (blue box) and detector part (red box). Each part is realized as a dot in a well (DWELL)-structure: a) the top draft shows a cut through a couple of stacked quantum dots (QDs). In general the QDs have a different height h1 and h2. The activation energies〖 ε〗_QD1 and ε_QD2 are defined as the energy difference between the QD-groundstate and the conduction band edge of the barrier-material, b) the drawing on the bottom depicts a cut through the structure at a position without QDs. The quantum well QW1 with the corresponding width d1 ensures an efficient electron capture of the DWELL-injector. The barrier B covers the wetting layer WL1 of the quantum dot layer QD1 in order to increase the electron capture efficiency of the injector. QW1 is clearly separated from the DWELL-detector by a distance denoted with D in order to prevent an injection of electrons from the QW1 into QW2 with the width d2.
The scheme shows the growth sheet of the proposed IQMIP-device (left). The right shows the bandstructure of the device once for a cut through the wetting layer and once through a couple of stacked quantum dots. Quantum dot layer 1 (QD1) and quantum well 1 (QW1) constitute the injector-dot in a well (DWELL) part of the IQMIP. QD2 and QW2 form the detector-DWELL part of the IQMIP with a spectral response in the long wavelength infrared range. At high temperatures the electron injection into the detector-DWELL occurs mainly by phonon assisted tunnelling through the QD1-layer.
The graph shows the result of a 3D simulation for the IQMIP-device shown in fig. 2. The bound states of the system are marked by the set of horizontal lines and the spread of each line symbolizes the overlap of the corresponding wavefunction. The blue lines label the quantum dot (QD) states of the injector-DWELL (QD1), the violet lines label states that are strongly localized towards the quantum well (QW) of the injector-DWELL, the red lines label QD states of the detector-DWELL (QD2), and the green lines the states that are strongly localized along the wetting layer (WL). The s- and p-state of QD2 hybridize into bounding (s2-b, p2-b) and anti-bounding (s2-a, p2-a) states. The p2-b and p2-a are energetically spaced within the range of acoustical phonons. The energy difference between the injector-DWELL ground-state (GS) and the detector-DWELL-GS is 73 meV, i.e. approximately the energetic range of twice the LO-phonon energy.This enables to investigate resonant LO-phonon assisted injection as a function of the bias voltage. The bound to quasibound transition energy of the detector-DWELL is in the range of 120-170 meV, i.e. the transition energy between the GS and the WL-states.
The graph shows the wavefunctions of the bounding (left) and anti-bounding p-state (right) of the QD1 layer. The z-axis shows the electron probability density along a 2D cut through the center of the QDs.
Simulations with different lateral quantum dot (QD) dimension have been performed in order to investigate the influence of an inhomogeneous size distribution, i.e. for 18 and 15 nm. The height of the QDs was kept at 6 nm for both simulation-runs, due to the possibility to employ the Indium-flush technique in order to achieve these dimensions. It can be seen that the energy difference between the s- and p-shell of the respective QDs is in the range of 1.2-1.7 meV.
XRD patterns of the products: (a) containing MWNTs, (b) containing MWNTs/ZnO nanocomposites.
SEM images of the products: (a) containing MWNTs, (b) containing MWNTs/ZnO nanocomposites.
SAD pattern of individual MWNTs.
Raman spectrum of the products containing MWNTs.
IR spectra of the products: (a) containing MWNTs in 400°C, (b) containing MWNTs in 550°C, (c) containing MWNTs in 600°C obtained finally; (d) containing MWNTs/ZnO in 550°C, (e) containing MWNTs/ZnO in 600°C.
EDS spectrum of the products containing MWNTs/ZnO nanocomposites.
Schematic of the cutting process using abrasive papers as nanoscissors.
TEM images of cutting nanotubes with nanoscissors. (a) TEM image of MWCNTs before cutting. (b) A MWCNT is not yet sheared off by nanoscissors. The inset shows the magnified section of the cut region. (c) A high resolution TEM image showing the structure of a MWCNT after cutting.
SEM images of the shortened MWCNTs after cutting. (a) a low magnification image of shortened CNTs, and (b) a typical shortened CNT.
Histogram of the length distribution of MWCNTs after cutting.
Zeta potential curves of MWCNTs before and after cutting. The insert shows photographs of dispersibility of MWCNTs before cutting (a) and after cutting (b).
Surface SEM images of shorten MWCNTs/Cu composite thin film prepared by combined electrophoresis and electroplating techniques.
(a) and (b) Surface and cross-sectional morphology photo by SEM after Ag particles were plated on the surface; (c) local high magnification picture of (a); (d) SEM picture of the surface without H2O2 and HF etching after Ag particles were removed.
(a) and (b) Surface and cross-sectional morphology photo by SEM after etched by H2O2 and HF for 10 minutes; (c) SEM picture of the cross section after etched by H2O2 and HF for one hour; (d) TEM picture of a single nanowire.
Schematic diagram about evolution and fabrication of Si NWs arrays by Ag-catalyzed etching.
Reflectance spectra of the samples etched by HF and H2O2 for different times.
Schematic diagram of broadband antireflection mechanism based on graded refractive index.