scholarly journals Optical and dielectric properties of polycrystalline gallium ferrite thin films on Pt/Si  substrates

Author(s):  
Monali Mishra ◽  
Smrutirekha Swain ◽  
Sukalyan Dash ◽  
Somdutta Mukherjee

Abstract In this work, GaFeO 3 thin films are deposited on Pt/Si substrates using sol-gel spin coating technique. The effect of these films on different properties such as: structural, optical and electrical properties are investigated. X- ray diffraction (XRD) confirms that GaFeO 3 has orthorhombic Pc2 1 n symmetry. Scanning electron microscopy reveals the uniform distribution of sol and crack free nature of the films. The optical absorption spectrum was recorded using DRS UV-Vis which showed the thin films are absorbed in the visible region. We have also performed experimentally which determines the flat band potential using Mott-Schottky equation. The width of the space charge region and charge carrier concentration of the thin films is also calculated. The dielectric properties of the thin films are also studied in this paper. This work opens up the possibility for the polycrystalline GaFeO 3 thin films to be used as phototelectrodes.

2014 ◽  
Vol 32 (4) ◽  
pp. 688-695 ◽  
Author(s):  
Munirah Munirah ◽  
Ziaul Khan ◽  
Mohd. Khan ◽  
Anver Aziz

AbstractThis paper describes the growth of Cd doped ZnO thin films on a glass substrate via sol-gel spin coating technique. The effect of Cd doping on ZnO thin films was investigated using X-ray diffraction (XRD), UV-Vis spectroscopy, photoluminescence spectroscopy, I–V characteristics and field emission scanning electron microscopy (FESEM). X-ray diffraction patterns showed that the films have preferred orientation along (002) plane with hexagonal wurtzite structure. The average crystallite sizes decreased from 24 nm to 9 nm, upon increasing of Cd doping. The films transmittance was found to be very high (92 to 95 %) in the visible region of solar spectrum. The optical band gap of ZnO and Cd doped ZnO thin films was calculated using the transmittance spectra and was found to be in the range of 3.30 to 2.77 eV. On increasing Cd concentration in ZnO binary system, the absorption edge of the films showed the red shifting. Photoluminescence spectra of the films showed the characteristic band edge emission centred over 377 to 448 nm. Electrical characterization revealed that the films had semiconducting and light sensitive behaviour.


2009 ◽  
Vol 1199 ◽  
Author(s):  
Danilo G Barrionuevo ◽  
Surinder P Singh ◽  
Maharaj S. Tomar

AbstractWe synthesized BiFe1-xMnxO3 (BFMO) for various compositions by sol gel process and thin films were deposited by spin coating on platinum Pt/Ti/SiO2/Si substrates. X-ray diffraction shows all the diffraction planes corresponding to rhombohedrally distorted perovskite BiFeO3 structure. The absence of any impurity phase in the films suggests the incorporation Mn ion preferentially to Fe site in the structure for low concentration. Magnetic measurements reveal the formation of ferromagnetic phase at room temperature with increased Mn substitution. On the other hand, ferroelectric polarization decreases with increasing Mn ion concentration. Raman studies suggest the dopant induced structural distortion.


2012 ◽  
Vol 531 ◽  
pp. 93-96
Author(s):  
Qian Li ◽  
Xi Feng Li

The effects of after-annealed temperature on the microstructure, optical and electrical properties of solution processed amorphous indium gallium zinc oxide (a-IGZO) thin films were investigated in this article. The X-ray diffraction results confirmed that all the films were an amorphous structure. A transmittance of more than 90% in the visible wavelength region was obtained. the a-IGZO thin films reached the lowest electrical resistivity of 9.44×104Ω•cm with the after-annealed temperature of 300°C.


2009 ◽  
Vol 1199 ◽  
Author(s):  
Songwei Han ◽  
Shengwen Yu ◽  
Jinrong Cheng

AbstractIn this work, Ba0.6Sr0.4TiO3(BST) thin films were deposited on Ti substrates using conductive La0.5Sr0.5CoO3 (LCSO) as buffer layers. Both BST and LSCO films were prepared by sol-gel methods. The structure and morphology of BST and LSCO films were analyzed by X-ray diffraction (XRD). XRD results show that both BST and LSCO films have perovskite structure with random orientation. The dielectric properties of BST films were dependent on the thickness of LSCO buffer layers. Upon using LSCO buffer layers, the dielectric properties of BST films were significantly improved. The dielectric constant, tunability, and dielectric loss of BST thin films for LSCO of 150 nm achieved about 453, 0.032 and 31.26% respectively.


1998 ◽  
Vol 322 (1-2) ◽  
pp. 323-328 ◽  
Author(s):  
Di Wu ◽  
Ai-dong Li ◽  
Chuan-Zhen Ge ◽  
Peng Lü ◽  
Chun-Yi Xu ◽  
...  

2003 ◽  
Vol 784 ◽  
Author(s):  
A. Dixit ◽  
P. Bhattacharaya ◽  
S. B. Majumder ◽  
R. S. Katiyar ◽  
A. S. Bhalla

ABSTRACTFerroelectric thin films of BaZrxTi1-xO3 (BZT) were deposited on platinum (Pt) and platinized silicon (Pt/Si) substrates by sol-gel and pulse laser deposition technique respectively. The structure and preferred orientation of the films were examined by x-ray diffraction measurements. The phase formation of sol-gel derived BZT films were found to be at high temperature (1100°C) compare to the pulse laser deposited BZT films ∼ 700°C. Polycrystalline films were observed by both techniques. Ferroelectric nature of the films was confirmed by hysteresis and capacitance-voltage characteristics using platinum top electrodes. Dielectric constant as well as loss was found to decrease by increasing Zr contents. Surface morphology predicted smooth crack free surface.


2006 ◽  
Vol 514-516 ◽  
pp. 1155-1160 ◽  
Author(s):  
Talaat Moussa Hammad

Sol gel indium tin oxide thin films (In: Sn = 90:10) were prepared by the sol-gel dipcoating process on silicon buffer substrate. The precursor solution was prepared by mixing SnCl2.2H2O and InCl3 dissolved in ethanol and acetic acid. The crystalline structure and grain orientation of ITO films were determined by X-ray diffraction. The surface morphology of the films was characterized by scanning electron microscope (SEM). Optical transmission and reflectance spectra of the films were analyzed by using a UV-visible spectrophotometer. The transport properties of majority charge carriers for these films were studied by Hall measurement. ITO thin film with electrical resistivity of 7.6 ×10-3 3.cm, Hall mobility of approximately 2 cm2(Vs)-1 and free carrier concentration of approximately 4.2 ×1020 cm-3 are obtained for films 100 nm thick films. The I-V curve measurement showed typical I-V characteristic behavior of sol gel ITO thin films.


2002 ◽  
Vol 737 ◽  
Author(s):  
R.E. Melgarejo ◽  
M.S. Tomar ◽  
A. Hidalgo ◽  
R.S. Katiyar

ABSTRACTNd substituted bismuth titanate Bi4-xNdxTi3O12 were synthesized by sol-gel process and thin films were deposited on Pt substrate (Pt/TiO2/SiO2/Si) by spin coating. Thin films, characterized by X-ray diffraction and Raman spectroscopy, shows complete solid solution up to the composition x < 1. Initial results indicate that the ferroelectric polarization increases with increasing Nd content in the film with 2Pr = 50μC/cm2 for x = 0.46, which may have application in non-volatile ferroelectric memory devices.


2010 ◽  
Vol 93-94 ◽  
pp. 231-234
Author(s):  
B. Hongthong ◽  
Satreerat K. Hodak ◽  
Sukkaneste Tungasmita

Strontium substituted hydroxyapatite(SrHAp) were fabricated both in the form of powder as reference and thin film by using inorganic precursor reaction. The sol-gel process has been used for the deposition of SrHAp layer on stainless steal 316L substrate by spin coating technique, after that the films were annealed in air at various temperatures. The chemical composition of SrHAp is represented (SrxCa1-x)5(PO4)3OH, where x is equal to 0, 0.5 and 1.0. Investigations of the phase structure of SrHAp were carried out by using X-ray diffraction technique (XRD). The results showed that strontium is incorporated into hydroxyapatite where its substitution for calcium increases in the lattice parameters, and Sr3(PO4)2 can be detected at 900°C. The SEM micrographs showed that SrHAp films exhibited porous structure before develop to a cross-linking structure.


2019 ◽  

Transparent conducting oxide (TCO) thin films are materials of significance for their applications in optoelectronics and sun powered cells. Fluorine-doped tin oxide (FTO) is an elective material in the advancement of TCO films. This paper reports the impact of fluorine doping on structural, optical and electrical properties of tin oxide thin films for solar cells application. The sol-gel was prepared from anhydrous stannous chloride, SnCl2 as an originator, 2-methoxyethanol as a solvent, di-ethanolamine as a preservative and ammonium fluoride as the dopant source. FTO precursor solution was formulated to obtain 0, 5, 10, 15 and 20 % doping concentration and deposited on glass substrates by means of spin coater at the rate of 2000 rpm for 40 seconds. After pre-heated at 200 oC, the samples were annealed at 600 oC for 2 h. The structural, optical and electrical characteristics of prepared films were characterized using X-ray diffraction (XRD) analysis, UV-visible spectroscopy and electrical measurement. X-ray diffraction (XRD) investigation of the films demonstrated that the films were polycrystalline in nature with tetragonal-cassiterite structure with most extraordinary pinnacle having a grain size of 17.01 nm. Doping with fluorine decreases the crystallite size. There was increment in the absorbance of the film with increasing wavelength and the transmittance was basically reduced with increasing fluorine doping in the visible region. The energy band gaps were in the range of 4.106-4.121 eV. The sheet resistance were observed to decrease as the doping percentage of fluorine increased with exception at higher doping of 15 and 20 %. In view of these outcomes, FTO thin films prepared could have useful application in transparent conducting oxide electrode in solar cell.


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