PRISA: a simple software for determining refractive index, extinction co-efficient, dispersion energy, band gap, and thickness of semiconductor and dielectric thin films
A simple user-friendly software named PRISA has been developed to determine optical constants (refractive index and extinction co-efficient), dispersion parameters (oscillator energy and dispersion energy), absorption co-efficient, band gap and thickness of semiconductor and dielectric thin films from their measured transmission spectrum, only. The thickness, refractive index, and extinction co-efficient of the films have been derived using Envelope method proposed by Swanepoel. The absorption co-efficient in the strong absorption region is calculated using the method proposed by Connel and Lewis. Subsequently, both direct and indirect bandgap of the films is estimated from the absorption co-efficient spectrum using Tauc plot. The codes for the software are written in Python and the graphical user interface is programmed with tkinter package of Python. It provides convenient input and output of the measured and derived data. The software has a feature to retrieve transmission spectrum using the derived parameters in order to check their reliability. The performance of the software is verified by analyzing numerically generated transmission spectra of a-Si:H amorphous semiconductor thin films, and experimentally measured transmission spectra of electron beam evaporated HfO2 dielectric thin films as examples. PRISA is found to be much simpler and accurate as compared to the other freely available softwares. To help other researchers working on thin films, the software is made freely available at https://www.shuvendujena.tk/download.
Total and partial density of states, frequency dependent complex refractive index including extinction coefficient, optical conductivity and transmission of MgxZn1-xO (0 \leq x \leq 1) in rocksalt and wurtzite phases are calculated using full potential linearized augmented plane wave (FP-LAPW) method. The real part of refractive index decreases while the extinction coefficient, optical conductivity and transmission for rocksalt phase increases with the increase in Mg concentration. In wurtzite phase, ordinary and extraordinary indices decreases while extinction coefficient, optical conductivit…
Herein, the concept of point of darkness based on polarized light phase difference and absorption of light is demonstrated by simulations using low refractive index and extinction coefficient semiconductor and dielectric, and high refractive index nonoxidizing metal multilayer thin film structures. Several multilayer sensor configurations show great sensitivity to thickness and refractive index variation of the detectable material by measuring the reflectivity ratio Ψ and phase shift Δ. Focus is on such multilayers, which have sensitivity to both parameters (Ψ, Δ) in the visible spectral range…
Recently, chalcogenide glass based phase change materials (PCMs) have shown utility as a tuning material for a range of nanophotonic devices. Owing to their low loss, ultrafast switching speeds and wide waveband operation, PCMs are integrated in an increasing number of next generation tunable components, including integrated photonic switches, metasurface optics and tunable spectral filters. Nonetheless, modelling of PCM-based devices is challenging, both in terms of accurate representation of experimentally-derived material properties in different phase states, and standardization of results …
Room-temperature optical constants of crystalline Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ were determined using data extracted from Brillouin light scattering spectra. Optical extinction coefficient-to-refractive index ratios at a wavelength of 532 nm were obtained from bulk phonon peak linewidth and frequency shift measurements and range from $0.19 \leq 2κ/n \leq 0.29$ for directions close to the crystallographic $c$-axis. These ratios, and optical extinction coefficients, absorption coefficients, and imaginary parts of the dielectric function determined from these ratios and known refractive index, ar…
We report on the complex dielectric tensor components of four chalcopyrite semiconductors in the optical energy range (1.4-5.2 eV, from 0.9 eV for CuInSe2) determined at room temperature by spectroscopic ellipsometry. Our results were obtained on single crystals of CuInSe2, CuGaSe2, CuInS2, and CuGaS2. Values of refractive indices n, extinction coefficients k and normal-incidence reflectivity R in the two different polarizations are given and compared with earlier data where available. We analyze in detail the structures of the dielectric function observed in the studied energy region. Critica…
The structural, electrical, optical, and mechanical characteristics of the lead-free halide double perovskites Cs2NaTlX6 X = F, Cl, Br are calculated by utilizing PBE functional within generalized gradient approximation GGA under the context of density functional theory DFT.The structural properties such as lattice parameter, cell volume, total energy, bulk modulus, pressure derivative, and tolerance factor are computed at equilibrium.The electronic density of states reveals the semiconducting nature of the compound and the band structure exhibits the nature of the band gap to be direct.HSE06 …
Nanocomposites made of polymer films embedding silver nanoparticles were prepared by thermal annealing of poly-(vinyl) alcohol films containing AgNO3. Low (2.5% w:w) and high (25% w:w) doping concentration of silver nitrate were considered as well as their effect on the optical properties of thin (30 nm) and thick (300 nm and more) films. The topography and the optical properties (refractive index $n$ and extinction coefficient $k$) of such films were studied by atomic force microscopy and spectroscopic ellipsometry. For a given doping level, the parameters of the surface plasmon-polariton res…
Thin films of CdTe were deposited on glass substrates by thermal evaporation. From the XRD measurements itis found that the films are of zinc-blende-type structure. Transmittance, absorption, extinction, and refractive coefficients are measured. Electronic structure, band parameters and optical spectra of CdTe were calculated from ab initio studies within the LDA and LDA+U approximations. It is shown that LDA underestimates the band gap, energy levels of the Cd-4d states, s-d coupling and band dispersion. However, it calculates the spin-orbit coupling correctly. LDA+U did not increase much the…
Effects of thermal annealing and film thickness on the structural and optical properties of indium-tin-oxide thin films
Center for Alloy Innovation and Design (CAID), State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University（西安交通大学合金创新与设计中心，材料力学行为国家重点实验室）
Phase-change materials (PCMs), which are well-established in optical and random-access memories, are increasingly studied for emerging topics such as brain-inspired computing and active photonics. These applications take advantage of the pronounced reflectivity and resistivity changes that accompany the structural transition in PCMs from their amorphous to crystalline state. However, PCMs are typically fabricated as thin films via sputtering, which is costly, requires advanced equipment, and limits the sample and device design. Here, we investigate a simpler and more flexi-ble approach for app…
