Investigation of Annealing on the Structural and Optical Properties of Chemical Bath Deposited ZnSe Quantum Dot Thin Films

2012 ◽  
Vol 229-231 ◽  
pp. 10-13
Author(s):  
Liang Yan Chen ◽  
Chao Fang

ZnSe thin films were obtained through chemical bath deposition method. Structural and optical properties of as deposited and annealed samples were investigated by X-ray Diffraction and spectrophotometer. The as deposited thin films were in nanocrystalline, with lots of strain and a blue shift of optical band gap. After annealing, the crystal grain gained, the strain eased and optical band gap enlarged. And it suggested that annealing can ease the quantum effect of chemical bath deposited ZnSe thin films.

2005 ◽  
Vol 905 ◽  
Author(s):  
B. Yang ◽  
Y. M. Lu ◽  
C. Neumann ◽  
A. Polity ◽  
C. Z. Wang ◽  
...  

AbstractDelafossite-type CuAlO2 thin films have been deposited by radio frequency (RF) reactive sputtering on sapphire using a CuAlO2 ceramic target. A study of structural and optical properties was performed on films of varying deposition parameters such as substrate temperature and oxygen partial pressure and also post annealing. The crystalline phase in the films was identified to be the delafossite structure by x-ray diffraction. The optical properties, such as the wavelength dependence of the transmittance and the band gap, were determined. The average transmittance is 80% in the wavelength range of 400-1500 nm and the band gap is 3.81 eV.


2015 ◽  
Vol 1109 ◽  
pp. 544-548 ◽  
Author(s):  
Jian Bo Liang ◽  
Xu Yang Li ◽  
Naoki Kishi ◽  
Tetsuo Soga

Single phase CuO films have been successfully synthesized by thermal oxidation of cupper foil in air with water vapor. The structural and optical properties of CuO films were investigated. It is observed that the grain size increases with increasing the oxidation temperature. The optical band gap of CuO film is determined by the transmittance and reflectance spectra.


2014 ◽  
Vol 938 ◽  
pp. 103-107
Author(s):  
V. Gowthami ◽  
M. Meenakshi ◽  
N. Anandhan ◽  
Chinnappanadar Sanjeeviraja

Nickel oxide has been widely used as material for antiferromagnetic, electrochromic display and functional layer for chemical sensors. Nickel oxide thin films of various molarities were deposited using a simple nebulizer technique and the substrate temperature was fixed at 350C. The effect of the molarity of precursor solution on structural and optical properties was studied using X-ray diffraction (XRD) and UV-Vis-NIR spectrometer techniques respectively. The band gap of the material was confirmed by photoluminescence spectrometer. It is found that increase in the molarity of 10ml volume of the sprayed solution leads to the increasing in film thickness. X-ray diffraction studies indicated cubic structure and the crystallites are preferentially oriented along (1 1 1) plane. It is also found that as the concentration of the solution increases the transmittance decreases, consequently the band-gap energy wanes from 4.0 eV to 3.2 eV.


Crystals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 132 ◽  
Author(s):  
Theopolina Amakali ◽  
Likius. S. Daniel ◽  
Veikko Uahengo ◽  
Nelson Y. Dzade ◽  
Nora H. de Leeuw

Zinc oxide (ZnO) is a versatile and inexpensive semiconductor with a wide direct band gap that has applicability in several scientific and technological fields. In this work, we report the synthesis of ZnO thin films via two simple and low-cost synthesis routes, i.e., the molecular precursor method (MPM) and the sol–gel method, which were deposited successfully on microscope glass substrates. The films were characterized for their structural and optical properties. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for piezoelectric applications. The surface roughness derived from atomic force microscopy (AFM) analysis indicates that films prepared via MPM were relatively rough with an average roughness (Ra) of 2.73 nm compared to those prepared via the sol–gel method (Ra = 1.55 nm). Thin films prepared via MPM were more transparent than those prepared via the sol–gel method. The optical band gap of ZnO thin films obtained via the sol–gel method was 3.25 eV, which falls within the range found by other authors. However, there was a broadening of the optical band gap (3.75 eV) in thin films derived from MPM.


2015 ◽  
Vol 814 ◽  
pp. 44-48 ◽  
Author(s):  
Ling Huang ◽  
Hong Mei Deng ◽  
Jun He ◽  
Lei Lei Chen ◽  
Ping Xiong Yang ◽  
...  

Cu2ZnSnS4and Cu2ZnGeS4thin films made from the earth abundant and non-toxic materials are quaternary semiconducting compounds which have received increasing interest for solar cells applications. Cu2ZnSnS4and Cu2ZnGeS4thin films have been synthesized by sulfurization of radio frequency magnetron sputtered precursors. The structural and optical properties of the thin films have been investigated and discussed. The result of X-ray diffraction demonstrates that the Cu2ZnSnS4and Cu2ZnGeS4thin films have kesterite (KS; space groupI) crystal structure. An obvious blue shift is observed in the Raman spectra as smaller Ge replaces Sn. It is due to the fact that the radius of Ge cation is smaller than that of Sn cation , which results in the shrink of the lattice. Further transmission spectra demonstrate that the values of band gap for CZTS and CZGS thin films are 1.54 eV and 1.98 eV, respectively.


2011 ◽  
Vol 685 ◽  
pp. 98-104
Author(s):  
Ling Shen ◽  
Cheng Shen ◽  
Jie Yang ◽  
Fei Xu ◽  
Zhong Quan Ma

In this paper, aluminum–doped nano-crystalline zinc oxide (ZnO:Al or AZO) thin films were deposited on fused quartz substrate by pulsed laser ablation at various temperatures. The physical phase and surface morphology were characterized by using X-ray diffraction (XRD) and atomic force microscope (AFM), respectively. The variation of the optical band gap (Egopt) of the films with the temperature was measured through transmittance in UV-VIS wavelength. The results showed that there was a blue shift of Egoptfrom 3.44 eV to 3.62 eV as the growing temperature decreased from 500°C to 200°C. The value of Egoptimmediately recurred from 3.30 to 3.35 eV after a thermal annealing of the samples at 700 °C, inclining to a normal value of bulk zinc oxide. The analyses of XRD and AFM testified that the presence of amorphous phase in the AZO films was the main reason for the blue shift of the optical band gap Egopt.


2019 ◽  
Vol 24 (5) ◽  
pp. 76
Author(s):  
Hiba A. Abdulla1 ◽  
Abdulla M. Ali1 ◽  
Khaleel I. Hassoon2

In this study, Structural and Optical Properties of titanium dioxide thin films are studied, TiO2 (Anatase) thin films were prepared by screen printing (SP) method. X-ray diffraction analysis showed that the structure of TiO2 films are polycrystalline and the lattice system is tetragonal. The main diffraction peak of TiO2 was (101) at 2θ=25ᵒ.  The data of optical absorption indicated that TiO2 thin films prepared by SP have a direct optical band gap (about 3.1eV).  The data of reflectivity was also used to calculate the band gap and was around 2.95 eV   http://dx.doi.org/10.25130/tjps.24.2019.093


2018 ◽  
Vol 12 (3) ◽  
pp. 199-208
Author(s):  
Maja Popovic ◽  
Mirjana Novakovic ◽  
Kun Zhang ◽  
Miodrag Mitric ◽  
Natasa Bibic ◽  
...  

Polycrystalline CrN thin films were irradiated with Xe ions. The irradiation-induced modifications on structural and optical properties of the films were investigated. The CrN films were deposited on Si(100) wafers with the thickness of 280 nm, by using DC reactive sputtering. After deposition, the films were implanted at room temperature with 400 keV Xe ions with the fluences of 5-20?1015 ions/cm2. The films were then annealed at 700 ?C in vacuum for 2 h. The combination of Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) was used for structural analyses, while changes in optical properties were monitored by spectroscopic ellipsometry. We also measured the electrical resistivity of the samples using a four point probe method. RBS analysis reveals that the concentration of Xe in the layers increases with ion fluence reaching the value of around 1.5 at.% for the highest ion dose, at a depth of 73 nm. XRD patterns show that the irradiation results in the decrease of the lattice constant in the range of 0.4160-0.4124 nm. Irradiation also results in the splitting of 200 line indicating the tetragonal distortion of CrN lattice. TEM studies demonstrate that after irradiation the columnar microstructure is partially destroyed within _90 nm, introducing a large amount of damage in the CrN layers. Spectroscopic ellipsometry analysis shows that the optical band gap of CrN progressively reduces from 3.47 eV to 2.51 eV with the rise in ion fluence up to 20?1015 ions/cm2. Four point probe measurements of the films indicated that as the Xe ion fluence increases, the electrical resistivity rises from 770 to 1607 ?Wcm. After post-implantation annealing crystalline grains become larger and lattice distortion disappears, which influences optical band gap values and electrical resistivity of CrN.


Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1064
Author(s):  
Iosif-Daniel Simandan ◽  
Florinel Sava ◽  
Angel-Theodor Buruiana ◽  
Ion Burducea ◽  
Nicu Becherescu ◽  
...  

ZnS is a wide band gap material which was proposed as a possible candidate to replace CdS as a buffer layer in solar cells. However, the structural and optical properties are influenced by the deposition method. ZnS thin films were prepared using magnetron sputtering (MS), pulsed laser deposition (PLD), and a combined deposition technique that uses the same bulk target for sputtering and PLD at the same time, named MSPLD. The compositional, structural, and optical properties of the as-deposited and annealed films were inferred from Rutherford backscattering spectrometry, X-ray diffraction, X-ray reflectometry, Raman spectroscopy, and spectroscopic ellipsometry. PLD leads to the best stoichiometric transfer from target to substrate, MS makes fully amorphous films, whereas MSPLD facilitates obtaining the densest films. The study reveals that the band gap is only slightly influenced by the deposition method, or by annealing, which is encouraging for photovoltaic applications. However, sulphur vacancies contribute to lowering the bandgap and therefore should be controlled. Moreover, the results add valuable information towards the understanding of ZnS polymorphism. The combined MSPLD method offers several advantages such as an increased deposition rate and the possibility to tune the optical properties of the obtained thin films.


2017 ◽  
Vol 268 ◽  
pp. 13-17 ◽  
Author(s):  
M.N. Ami Hazlin ◽  
Mohamed Kamari Halimah ◽  
Farah Diana Mohammad ◽  
M.F. Faznny ◽  
Shahrim Mustafa Iskandar

The glass samples of zinc borotellurite glass doped with dysprosium nanoparticles with chemical formula TeO20.7B2O30.30.7ZnO0.31-xDy2O3x (where x= 0.01, 0.02, 0.03, 0.04 and 0.05 molar fraction) have been fabricated by using melt quenching technique. In this study, the structural and optical properties of the zinc borotellurite glass doped with dysprosium nanoparticles were characterized by using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and UV-Vis spectroscopy. From the XRD, the amorphous nature of the glass samples has been confirmed. The infrared spectra revealed four obvious bands which are assigned for BO3, BO4 and TeO4 vibrational groups. The direct and indirect optical band gap, as well as Urbach energy, was calculated through absorption spectra obtained from UV-Vis spectroscopy. From the spectra, it is observed that both direct and indirect optical band gap decreases as the concentration of dysprosium nanoparticles increase. Other than that, the Urbach energy is observed to have an inverse trend with the optical band gap. The Urbach energy is increases as the concentration of dysprosium nanoparticles increases.


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