Optical and Electronic Analysis of Pure and Fe-Doped ZnO Thin Films Using Spectroscopic Ellipsometry and Kramers–Kronig Method

2019 ◽  
Vol 18 (01) ◽  
pp. 1850013 ◽  
Author(s):  
Maryam Motallebi Aghgonbad ◽  
Hassan Sedghi
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Spectroscopic Ellipsometry ◽  
Optical Band Gap ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Fe Doping ◽  
Gap Energy ◽  
Optical And Electronic Properties ◽  
Doped Zno

In the present work, pure and Fe-doped ZnO thin films were deposited on glass substrates by sol–gel method. Zinc acetate and iron nitrate were used as the starting material and dopant source, respectively. The concentration of Fe doping was 6[Formula: see text]at.% and 8[Formula: see text]at.%. The optical and electronic properties of pure and Fe-doped ZnO thin films such as refraction index, extinction coefficient, dielectric function and optical band gap energy of the layers were obtained by spectroscopic ellipsometry method in the wavelength range of 300–900[Formula: see text]nm. The incidence angle of the layers kept 70[Formula: see text]. Also data obtained by Kramers–Kronig relations were used for comparison. The influence of Fe-doping concentration on the optical and electronic properties of thin films was studied. The transmittance data of ZnO thin films showed that 6[Formula: see text]at.% Fe-doped ZnO thin film has the highest transmittance value. Dielectric function of pure ZnO films was found to be higher compared with Fe-doped ones. Also it can be deduced from the results that Fe doping influences the optical band gap energy of thin films.

Optical Characterization of Al-doped ZnO Films via Sol-gel Method Using Spectroscopic Ellipsometry

2020 ◽  
Vol 10 (5) ◽  
pp. 642-648
Author(s):  
Ehsan M. Aghkonbad ◽  
Hassan Sedghi ◽  
Maryam M. Aghgonbad
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Spectroscopic Ellipsometry ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Zno Films ◽  
Promising Alternative ◽  
Gap Energy ◽  
Doped Zno

Background: Al-doped ZnO thin films are considered as a promising alternative to ITO in optoelectronic applications. In this work, Al-doped ZnO thin films were prepared using sol-gel spin coating technique. Experimental: The optical properties of the films such as refractive index, extinction coefficient, dielectric function and the absorption coefficient were examined using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. The effect of Al doping on ZnO thin films with different Al concentrations was significant. Tauc relation was used to estimate the optical band gap energy of the films. Results: The calculated values of band gap energy were obtained between 3.10 to 3.25 eV. Also the fraction of voids was calculated using Aspnes theory. Conclusion: The free carrier concentration value was obtained in the order of 1019 cm-3.

A Study on Effect of Sol Aging Time on Optical Properties of ZnO Thin Films: Spectroscopic Ellipsometry Method

2019 ◽  
Vol 11 (2) ◽  
pp. 100-108 ◽  
Author(s):  
Ehsan Motallebi Aghkonbad ◽  
Maryam Motallebi Aghgonbad ◽  
Hassan Sedghi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Aging Time ◽  
Imaginary Part ◽  
Spectroscopic Ellipsometry ◽  
Annealing Temperature ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Gap Energy

Background: Due to wide band gap and large excitonic binding energy, being inexpensive, abundance in nature and easy synthesis ZnO is a promising candidate in many applications such as solar cells. Experimental: In the current work a series of ZnO thin films were deposited on glass substrates using sol-gel method to investigate the change in optical behavior of the film with sol aging time (asprepared, 8, 16, 24 and 32 hours) and the annealing temperature (300ᵒC and 500ᵒC). The optical properties of thin films were explored using spectroscopic ellipsometry method including the real and imaginary part of refractive index, real and imaginary part of dielectric function and band gap energy of the layers in the 300-900 nanometer wavelength range. Results: It can be deduced from the results that sol aging time and annealing temperature, affect the optical properties of the samples. Using single oscillator energy model of Wemple and Di Domenico parameters such as free charge carrier concentration ratio to effective mass, and plasma frequency, were calculated. Conclusion: The films prepared using 24 h aged solution, had the highest transmittance and the largest band gap energy.

Development of flexible Mg and Ga co-doped ZnO thin films with wide band gap energy and transparent conductive characteristics

2014 ◽  
Vol 585 ◽  
pp. 608-613 ◽  
Author(s):  
Seung Wook Shin ◽  
In Young Kim ◽  
G.V. Kishor ◽  
Yeong Yung Yoo ◽  
Young Baek Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Wide Band ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Wide Band Gap ◽  
Gap Energy ◽  
Doped Zno ◽  
Co Doped

Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

2015 ◽  
Vol 7 (3) ◽  
pp. 1923-1930
Author(s):  
Austine Amukayia Mulama ◽  
Julius Mwakondo Mwabora ◽  
Andrew Odhiambo Oduor ◽  
Cosmas Mulwa Muiva ◽  
Boniface Muthoka ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation ◽  
Optical Transition ◽  
Bulk Material ◽  
Band Gap Energy ◽  
Optical Absorbance ◽  
Gap Energy ◽  
Constituent Elements

 Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ≤ x ≤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the system’s network.

scholarly journals Effect of thickness on the optical properties of Gaas thin films

2013 ◽  
Vol 37 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Chitra Das ◽  
Jahanara Begum ◽  
Tahmina Begum ◽  
Shamima Choudhury
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Band Gap ◽  
Optical Band Gap ◽  
Visible Region ◽  
Solar Spectrum ◽  
Band Gap Energy ◽  
Optical Parameters ◽  
Gap Energy

Effect of thickness on the optical and electrical properties of gallium arsenide (GaAs) thin films were studied. The films of different thicknesses were prepared by vacuum evaporation method (~10-4 Pa) on glass substrates at a substrate temperature of 323 K. The film thickness was measured in situ by a frequency shift of quartz crystal. The thicknesses were 250, 300 and 500 nm. Absorption spectrum of this thin film had been recorded using UV-VIS-NIR spectrophotometer in the photon wavelength range of 300 - 2500 nm. The values of some important optical parameters of the studied films (absorption coefficient, optical band gap energy and refractive index; extinction co-efficient and real and imaginary parts of dielectric constant) were determined using these spectra. Transmittance peak was observed in the visible region of the solar spectrum. Here transmittance showed better result when thicknesses were being increased. The optical band gap energy was decreased by the increase of thickness. The refractive index increased by increasing thickness while extinction co-efficient and real and imaginary part of dielectric constant decreased. DOI: http://dx.doi.org/10.3329/jbas.v37i1.15684 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 1, 83-91, 2013

STRUCTURAL AND OPTICAL PROPERTIES OF UNDOPED AND SILVER, LITHIUM AND COBALT-DOPED ZnO THIN FILMS

2019 ◽  
Vol 27 (04) ◽  
pp. 1950138
Author(s):  
FATMA MEYDANERİ TEZEL ◽  
İ. AFŞIN KARİPER
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Optical Transmittance ◽  
Refraction Index ◽  
Zno Thin Films ◽  
High Temperature Furnace ◽  
Doped Zno ◽  
Ray Patterns ◽  
Temperature Furnace

Undoped and silver, lithium and cobalt-doped ZnO thin films have been successfully deposited on glass by chemical bath deposition (CBD). The reaction temperature was 50∘C and the films were annealed at 400∘C for 4[Formula: see text]h in a high temperature furnace. UV/VIS spectrum was used to determine optical transmittance, optical band gap ([Formula: see text] and absorbance values of Ag:ZnO, Co:ZnO, Li:ZnO and undoped ZnO thin films. Optical band gap ([Formula: see text] and absorbance values of undoped ZnO, Ag:ZnO, Co:ZnO and Li:ZnO thin films were found as 0.0158, 0.0064, 0.2638, 0.0956 and 3.24, 3.13, 3.27, 2.96 eV, respectively. Extinction coefficients and refraction indexes of the films were found to be 0.0096, 0.0038, 0.0068, 0.019 (extinction coefficient) and 1.26, 1.14, 1.66, 2.33 (refraction index), respectively. X-ray patterns of undoped ZnO, Ag:ZnO, Co:ZnO and Li:ZnO thin films were confirmed as amorphous.

Effect of Nb doping on morphology, crystal structure, optical band gap energy of TiO2 thin films

2014 ◽  
Vol 14 (3) ◽  
pp. 421-427 ◽  
Author(s):  
Deuk Yong Lee ◽  
Ju-Hyun Park ◽  
Young-Hun Kim ◽  
Myung-Hyun Lee ◽  
Nam-Ihn Cho
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Band Gap Energy ◽  
Tio2 Thin Films ◽  
Gap Energy ◽  
Nb Doping
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