Optical Characteristics of Zinc Oxide Films on Glass Substrates (original) (raw)
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2018
ZnO is an important II-VI semiconductor material for devices with possible applications such as piezo-electric transducers, spin functional devices, gas sensors, transparent electronics in solar cell, UV light emitters, surface acoustic waves and smart windows. In this study, the optical properties of ZnO thin films deposited on various substrates (quartz, sapphire, KDP, fused silica, BK7 glass, BaF2, GeO2 and diamond) have been investigated. In order to investigate the optical properties, a simulation program was developed. Famous computing language “MATLAB” was chosen as the coding language because of its high ability to generate ideal graph. The optical properties (refractive index, transmittance, extinction coefficient, absorption coefficient etc.) were studied as a function of wavelength in the range from 330nm to 1110nm. The refractive indices, extinction coefficients, absorption coefficients, dielectric constants were also studied. The transmittance spectra of ZnO thin films ...
Impact of Thickness and Substrate on Optical Properties of Zno Thin Films
Bangladesh Journal of Physics, 2020
During the last decades, ZnO has emerged as the most promising material in optoelectronic and optical applications in the visible region as well as in the infrared and UV region. It is because of the broad direct band gap of 3.37 eV at ambient temperature and high exciton binding energy of 60 meV allowing it to utilize the ultraviolet region. In this investigation, the optical characteristics of ZnO thin film of various thicknesses (300 nm, 600 nm, 900 nm) deposited on Quartz, Fused silica and Sapphire have been studied as a function of wavelength and photon energy. To obtain this, the equations for thin film have been derived, simulated and visualized by Matlab coding language. It is observed that with the increase in the photon energy, the refractive index and extinction coefficient show an increasing tendency. The results represent that among three substrates Fused silica has the lowest refractive index, reflectance and absorbance. In the visible region, the transmission spectra ...
Inspection of Optical Properties of ZnO Thin Films
2019
ZnO is a compound semiconductor with tetrahedral bonding configuration in a wurtzite structure. In a thin film device, it is a promising material for different optical and optoelectronic device applications. Also, among other possible applications are such as piezo-electric transducers, spin functional devices, gas sensors, transparent electronics in solar cell, UV light emitters, surface acoustic waves and smart windows etc. In this work, optical properties of ZnO Thin film deposited on three different substractes have been inspected. In order to investigate the optical properties of ZnO thin film simulation program “Matlab” was developed for its high efficiency to produce accurate graph. The optical properties of ZnO thin films were studied as a function of wavelength in the range from 300 nm to 1200 nm. The refractive index, absorption coefficient, extinction coefficient decrease with the increase in wavelength and their values are steady in the higher wavelength region. By comparing among the refractive indices of three substrates it was found that extraordinary KDP exhibits lowest refractive index. The transmittance spectra of ZnO thin films were investigated for different thicknesses (100nm, 450nm, 750nm). It was also observed that all the substrates exhibit a high transmittance of (80-95)% in the visible region. Moreover, in transmission spectra non-interference and interference effects were analyzed. No peaks in the transmission spectra reveals the evidence of non- interference effect. Interference fringes are represented by the maxima and minima in the interference term. Due to the interference effect the number of peaks increases with the increase in thickness. Thus, from the results it can be concluded that extraordinary KDP is the better substrate among other substrates for the deposition of ZnO thin film and give better causes for optoelectronic device applications.
High transparency of ZnO:In coated glass substrates
Journal of New Technology and Materials (JNTM), 2018
Undoped and heavily indium doped ZnO were deposited by dip-coating sol-gel method on glass substrates. When undoped ZnO was deposited the maximum value of transmittance decreases from 91% for bare substrate to less than 86%. However for ZnO:In coated substrate an unexpected high transmittance of 93.5% was obtained, exceeding that of bare glass substrate. To understand this particular behavior a theoretical model based on the propagation of electromagnetic waves in thin films was adapted to the studied samples and the measured transmittance spectra were perfectly fitted. The optical analysis of the two types of samples showed that the deposited films are dense inside the film while their refractive index decreases for the surface layers. Besides, it was noted that even if the preparation conditions are strictly identical, the heavily doped ZnO films is thicker and less dense then that of undoped ZnO. These results agree with AFM and SEM observations. The particular optical behavior described in this paper could be very beneficial for optical, optoelectronic and solar applications.
Inspection of Optical Properties of ZnO Thin Films Deposited on Different Substrates
IOSR Journals , 2019
ZnO is a compound semiconductor with tetrahedral bonding configuration in a wurtzite structure. In a thin film device, it is a promising material for different optical and optoelectronic device applications. Also, among other possible applications are such as piezo-electric transducers, spin functional devices, gas sensors, transparent electronics in solar cell, UV light emitters, surface acoustic waves and smart windows etc. In this work, optical properties of ZnO Thin film deposited on three different substractes have been inspected. In order to investigate the optical properties of ZnO thin film simulation program "Matlab" was developed for its high efficiency to produce accurate graph. The optical properties of ZnO thin films were studied as a function of wavelength in the range from 300 nm to 1200 nm. The refractive index, absorption coefficient, extinction coefficient decrease with the increase in wavelength and their values are steady in the higher wavelength region. By comparing among the refractive indices of three substrates it was found that extraordinary KDP exhibits lowest refractive index. The transmittance spectra of ZnO thin films were investigated for different thicknesses (100nm, 450nm, 750nm). It was also observed that all the substrates exhibit a high transmittance of (80-95)% in the visible region. Moreover, in transmission spectra non-interference and interference effects were analyzed. No peaks in the transmission spectra reveals the evidence of non-interference effect. Interference fringes are represented by the maxima and minima in the interference term. Due to the interference effect the number of peaks increases with the increase in thickness. Thus, from the results it can be concluded that extraordinary KDP is the better substrate among other substrates for the deposition of ZnO thin film and give better causes for optoelectronic device applications.
Optik, 2020
Highly transparent zinc oxide thin films with varied layer thicknesses have been prepared on microscopic glass substrates at 200 °C. Films thickness was measured by stylus profilometer. The films have been investigated for their structure using X-Ray diffraction; the patterns showed their amorphous nature. The dispersion parameters i.e. refractive index (n) and extinction coefficient (k) are computed in the wavelength range (350-2500 nm). The Tauc model was used to determine the optical band gap and Urbach tail with direct allowed transitions. The real and imaginary parts of the high frequency dielectric constant were discussed. Other parameters such as penetration depth, cutoff wavelength, dissipation factor, volume and surface energy loss functions, reflection loss factor, optical, electrical and thermal conductivities have also been determined. A systematic study of a wide range of optical parameters of ALD prepared ZnO films can serve as a valuable data source and can enrich the knowledge of the studied material.
Optical and structural properties of thin films of ZnO at elevated temperature
Zinc oxide (ZnO) thin films were prepared on glass substrate by sol-gel dip-coating method. The paper presents the properties of zinc oxide thin films deposited on soda-lime-glass substrate via dip-coating technique, using zinc acetate dehydrate and ethanol as raw materials. The effect of withdrawal speed on the crystalline structure, surface morphology and optical properties of the thin films has been investigated using XRD, SEM and UV-Vis spectrophotometer. X-ray diffraction study shows that all the films have hexagonal wurtzite structure with preferred orientation in (0 0 2) direction and transmission spectra showed highly transparent films with band gap ranging from 3.78 to 3.48 eV.
Defect and Diffusion Forum, 2013
The refractive index and extinction coefficient in infrared spectrum of the polycrystalline silicon films with different doped dosages, base on the inverse calculation, are obtained by means of utilizing the measured reflectance and transmittance of a layer of material and multilayer films, and the equations derived from photonics and electromagnetic theory. The calculation results demonstrate that the refractive index of the doped polycrystalline silicon films decreases with the doped dosages increasing and the extinction coefficient increases with the doped dosages increasing for a given wavelength. This method used for determining the refractive index and extinction coefficient of the polycrystalline silicon films is effective and has the advantage of that the measured samples are fabricated simply.
Comparative optical study of ZnO thin films prepared by SILAR method
PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019
ZnO thin films find verity of applications in scientific and electronic world. Due to specific features of ZnO thin films like wide band gap energy, transparency in visible region, photoluminescence etc it is considered as a favorable material in optoelectronic and solar cell devices. Thus optical studies play an important role in selectivity of of ZnO thin films in different fields. The present work is carried out in a way to compare and to study the optical properties of ZnO thin films prepared with out annealing and annealed at 350 0 C. The method of preparation adopted was Successive Ion Layer Adsorption and Reaction (SILAR). Here precursor medium of 0.1M Zn salt was prepared and SILAR of 50 dip cycles were executed. Thus obtained first film was not annealed and the second film annealed for 350 0 for two hours. Thus obtained respective samples S1 and S2 were investigated with UV-Visible spectrometer and absorbance and transmittance values were obtained. About 350-400nm wave length the absorbance of S1 was found greater than that of S2. Around 400 nm a spike was observed for S2, which could be due to absorption corresponding to band gap. Form absorption spectrum maximum value of each samples were noted. From the transmission spectrum it was observed that between 350-400nm transmittance of S2 was greater than S1. The maximum values of transmittance were compared and reported. Thus calculated values of extinction coefficient and reflectance were plotted against wave length and it was observed that, extinction coefficient variation as similar to absorption, S1 is greater than S2 in the above mentioned range of wave lengths and reflectance were comparable for both samples for entire range of wave lengths. The variation of extinction coefficient and reflectance of respective samples were studied and minimum value of extinction coefficient was reported. Photon energy Vs (αhν) 2 plot were prepared for the samples and variations were recorded. It is observed from the study that absorption and extinction coefficient of S1 increases where as transmittance decreases between 350-400nm wave lengths. On the other hand reflectance and energy curves are comparable for both the samples. Hence SILAR was found to be an effective preparatory method for ZnO thin films.
Investigation of zinc oxide thin film by spectroscopic ellipsometry
2008
ZnO films were deposited on glass substrates by magnetron RF-sputtering. An accurate determination of the optical constants of these films is extremely important prior to its application in optical devices and spectroscopic ellipsometry provides a reasonably accurate method for the determination of optical constants of thin films. In this study, we present the results gained by analyzing spectroscopic ellipsometry of ZnO thin film combined with comparison of transmission spectroscopy measured on a UV-VIS-NIR spectrophotometer. Ellipsometry data have been fitted with a model including a glass substrate and a ZnO film plus a surface void layer on top. From this fitting the refraction index (n), extinction coefficient (k) and thickniess (d) of the sputtered ZnO films were determined. By using the gained n, k and d values the transmission spectrum was theoretically calculated and compared with the experimentally obtained transmission one. As a result of the combined spectroscopic ellipsometry and transmission analysis, there was the good correlation in comparison.