Each periodic thickness of the lateral gradual multilayer changes in the horizontal direction corresponding to different energies, so the energy bandwidth can be expanded to a correspondingly large range. XRR results for gradual lateral Mo/Si multilayers at different positions (translations are placed on the Y-axis to make all curves clear).
Polarimeter in Beijing Synchrotron Radiation Facility (BSRF) and application
Schematic representation of the polarimeter at the BSRF: (1) chamber; (2) azimuth angle of the polarizer; (3) x-y collimator translation rate; (4) detector I0; (5) polarizer; (6) moving swings; (7) sample phase; (8) rotary stage to change the azimuth angle of the analyzer; (9) analyzer; and (10) main detector. Detailed results of polarization optimization at other energies are shown in Table 8 [20].
Conclusion
Acknowledgements
Author details
Transmission properties of multilayer structure in the soft x-ray spectral region and its application to the design of quarter-wave plates at 13 and 4.4 nm. Selection of our books indexed in the Book Citation Index in Web of Science™ Core Collection (BKCI).
TOP 1%
Introduction
However, the role of the polar IPA solvent in the synthesis of FAPbIxBr3−x perovskites is still not clear because the reaction rate is very high. In this chapter, we present the role of the IPA solvent in the synthesis of FAPbIxBr3−x perovskites, including the effect of Br incorporation into the films through a two-step dissolution process using spectroscopic ellipsometry (SE) as well as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).
Experimental section
The fine structures of the α-PbIxBr2-x and perovskite FAPbIxBr3-x thin films were also evaluated using X-ray diffraction (Bruker D8 ADVANCE ECO) with the diffractometer in Bragg-Brentano mode using Cu Kα radiation with a Lynxeye XE detector, Fourier transform infrared spectroscopy (Shimadzu spectrometer, IRTracer-100), field emission scanning electro nen microscopy (FESEM; S4800, Hitachi High Technologies, Japan) with energy-dispersive X-ray spectroscopy (EDX) (Bruker XFlash 5030/Quantax 400) and atomic force microscopy (AFM; NanonavieII/. SPI-3800, Hitachi High-Tech Science, Japan) to support the results of the SE analysis.
Results and discussion
- Characterization of FAPbI x Br 3−x perovskite films
- SE study of perovskite FAPbI x Br 3−x films
The best-fit
Energy (eV)
The n and k spectra of the α-PbIxBr2-x bulk component together with the optical model used for the spectra fitting are shown in Fig. 3b. However, the (n,k) spectra calculated using different optical models deviated widely from the measured spectra, suggesting that modeling of the optical constant for the transition phase from α-PbIxBr2−x to the FAPbIxBr3−x perovskite structure should be considered at any time.
Energy (eV)χ2 =0.71
- Effect of x on the fine structure of FAPbI x Br 3−x perovskite films
- Role of IPA solvent in the synthesis of FAPbI x Br 3−x perovskites
The onset of the optical transition (ω0) shifted to 1.75 eV and was almost independent of the immersion time above 300 s. Among the four optical transitions, the lowest energy shift of the ω2 component from 3.85 to 3.4 eV was evident and attributed to the 6s-6p transition of Pb2+. The energy of the lowest exciton decreases significantly with increasing dimension and was 1.633 eV for 0D, 2D, and 3D lattice compounds, respectively.
These results provide an analogy that the process for the formation of FAPbIxBr3−x perovskite from a-PbIxBr2−x is attributed to the reduction of the crystal structure dimension based on [Pb(IBr)6]4−. Changes in optical transition for ω0, ω1, ω2 and ω3 of PbIxBr2−x immersed in FAIxBr1−x/IPA solution at different times. A spectroscopic ellipsometric study of organic-inorganic halide: FAPbIxBr3−x perovskite thin films by a two-step method http://dx.doi.org/10.5772/intechopen.70281 .
SE also showed an increase in refractive index for the FAPbIxBr3−x perovskite phase along with an increase in film thickness and void volume fraction. In addition, the prominent undercut absorption tail in the 3:2 film compared to the 3:1 film suggests that the defect originates from the increased grain boundary of the FAPbIxBr3−x (3:2) perovskite phase for the higher Br composition ratio.
PbBr 2 =3:1
In fact, XRD pattern and PL revealed that lattice parameter decreased with higher-edge emission peak energy when Br composition was increased. These findings imply that Br incorporation into FAPbIxBr3−x perovskite films promotes the densification of perovskite network, leading to the increase of the free volume as a void and film thickness. Despite immersion for only 10 s, the peak at 2θ = 12.7° attributed to the crystalline PbIxBr2−x (1 0 0) diffraction was observed, suggesting that the crystallization.
PbBr 2 =3:2
- Conclusions
- Theory and optical configuration of the photoelastic modulated imaging ellipsometry
- Two-dimensional measurement results for ellipsometric parameters, Stokes parameters, and Mueller matrix
The significant decrease in n is due to crystallization and the destruction of the mesoporous in a-PbIxBr2−x. Moreover, MPEM(θ,ΔP), RSAM(Ψ,Δ), and MA(A) represent the Mueller matrix of the PEM, the sample, and the analyzer, respectively. In this configuration, the optical axis of the PEM is at 0 with respect to the plane of incidence.
We present a technique to calibrate the PEM modulation amplitude using the Multiple Harmonic Intensity Ratio (MHIR) technique, the setup of which was the same as in the ellipsometric measurement [28]. Stokes vector measurement noise can be expressed in vector form {n}; therefore, the error {ε} can be expressed as {ε} = [A] 1{n}. K. row of the matrix [A] 1 of the phase-lock configuration can be expressed as [1 0 cos(ΔP) sin(ΔP)]T where ΔP= δ0sinωt is the phase lag of the PEM.
Trajectory of phase-locked PEM polarimetry on the Poincar'e sphere: the four specific polarization states are shown in the plot. Furthermore, the tuning curve of the liquid crystal variable radar (LCVR) was found to be sensitive to its extent and temperature to result in systematic errors and also affect the overall performance of the instrument [36]. Phase distribution of the measured quarter-wave plate while the azimuth angle was set to 0.
Azimuth angle distribution of the measured quarter waveplate with the azimuth angle set to (a) 0, (b) 30, and (c) 60.
Spectroscopic Ellipsometry - Application on the Classification of Diamond-Like Carbon Films
Classification of Diamond-Like Carbon Films
Experimental details
Samples #07 and #08 were prepared by a radio frequency (RF) magnetron sputtering method at a negative bias of 0.3 kV, a deposition time of 5 and 3 minutes with a working pressure of 10 Pa and an RF power of 150 W (to obtain ta-C:H or a-C:H films). Samples #09 and #10 were deposited by an electron cyclotron resonance chemical vapor deposition (ECRCVD) method at a negative bias voltage of 0.3 and 0.5 kV, a deposition time of 10 minutes with a working pressure of 0.5 Pa and an RF power of . Samples #11-13 were prepared by a plasma enhanced (PE)-CVD method at the same deposition time of 10 minutes and applied negative bias in the range of 0.0-0.5 kV (to obtain α-C:H or PLC films).
In the second part of the experiment, different types of DLC films were also deposited on the (100)-oriented p-type silicon single wafer substrate. Samples D and E were deposited by RF mag-Netron sputtering with negative bias voltage 0.3 kV, loading time 3 and 5 min with working pressure 20 Pa, RF power 150 W. Samples F-K were synthesized by RF-PE-CVD methods at the same 10 min deposition time.
XRR measurements (M03XHFMXP3, Mac Science) were obtained using a 1.54 Å wavelength Cu Kα source operating at an acceleration voltage of 40 kV and its currents of 15 mA under conditions of scan range and step size of 0.004°. Carbon K-edge NEXAFS spectra were measured in the energy range of 275–320 eV in an energy step of 0.1 eV.
SE-BEMA analysis
- Selection of standard materials
- Optical model establishment
The sp3/(sp3 + sp2) ratios of the DLC films were obtained by the NEXAFS method performed at BL3.2Ub of the Synchrotron Light Research Institute (SLRI) (a public organization), Nakhon Ratchasima, Thailand. In addition, the density and dielectric constant of DLC films were generally lower than those of crystalline diamond and graphite due to amorphization and hydrogenation. The Levenberg–Marquardt algorithm was used to check the fit of the (Ψ, Δ) spectra analysis.
Figure 2(b) shows the comparison of the dielectric functions of PG obtained from the above analysis and Ref. Figure 2(c) shows the simulation of GC based on the current dielectric function of PG. In the first stage of these simulation analyses, all the DLC films were simulated using models (c)–(h) where diamond is one of the basic standard materials.
However, the standard material of diamond cannot necessarily reflect the C(sp3) structure for all kinds of the current DLC films, which can be well represented instead. In the second stage, the models (i)–(l) using PE as one of the basic standard materials are therefore adapted to analyze the high hydrogen content and low density DLC films.
Results and discussion
- Results
- Discussions
The C and Si peaks on the RBS spectra of DLC films and substrates are profiled using the RBS fit calculation package. The sp2 content of the DLC films can be extracted by normalizing the resonance region corresponding to C 1 s → π* at 284.6 eV with the full spectral region. In the first stage, optical models (c)–(h) were applied to DLC films using diamond as one of the basic standard materials.
The optical energy gap Bv of DLC films is obtained from the Tauc-Lorentz model fit of the experimental data. Optical models (c) and (d) without void will be useful for the high-density and low-hydrogen content DLC films as follows. The DLC films with the density in the range of 1.4 < ρXRR < 3.0 g/cm3 corresponding to the types can be simulated by the optical models (e) or (f).
Thus, the hydrogen content should be the decisive factor affecting the optical properties of DLC films. SE spectral analysis based on Ek and En-max can facilitate the evaluation of DLC films.
Conclusions
Density, sp3 fraction and cross-sectional structure of amorphous carbon films determined by X-ray reflectivity and electron energy loss spectroscopy. Fine structure study of synchrotron radiation absorption near the X-ray edge of amorphous hydrogenated carbon films at different thicknesses. Spectroscopic Ellipsometry - Application to Classification of Diamond-like Carbon Films http://dx.doi.org/10.5772/intechopen.71727 149.
Structural analysis of amorphous carbon films by BEMA theory based on spectroscopic ellipsometry measurement. Determination of the sp3/sp2 ratio in tetrahedral amorphous carbon films by the effective medium approximation. Structural characterization of sputtered hydrogenated amorphous carbon films by solid-state nuclear magnetic resonance.
Hydrogen quantification of magnetron sputtered hydrogenated amorphous carbon (a-C:H) coatings produced at different bias voltages and their tribological behavior under different humidity levels. Spectroscopic ellipsometry - Application to the classification of diamond-like carbon films http://dx.doi.org/10.5772/intechopen.71727 151.
