Synthesis and Characterization of Semiconductor Composites Gas Sensors Based on ZnO Doped TiO2 Thin Films by Laser-Induced Plasma

2021 ◽  
Vol 900 ◽  
pp. 112-120
Author(s):  
Souad G. Khalil ◽  
Mahdi M. Mutter
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Electrical Characterization ◽  
X Ray Diffraction ◽  
Type Conductivity ◽  
Force Microscopy ◽  
Atomic Force ◽  
P Type

This work presents the development of n-type (TiO2) and p-type (ZnO) gas-sensitive materials from ZnO doped TiO2 thin films prepared by pulsed laser deposition technique (PLD) on a glass substrate as a gas sensor of CO2 gas. TiO2 gas-sensing layers have been deposited over a range of ZnO content (0, 20, and 40) wt %. The obtained thin films analysis by atomic force microscopy (AFM), and X-ray diffraction (XRD). Electrical characterization shows that TiO2:ZnO thin films were p-type conductivity and ZnO added was unable to change the composition to the n-type conductivity. There are notable gas-sensing response differences between n-type and p-type ZnO doped TiO2 thin film. The responses toward all tested oxidizing gases tend to increase with operating temperature for the n-type TiO2 films. Besides, the p-type ZnO doping results in a significant response improvement toward tested oxidizing gases such as CO2 gas at the low operating temperature of 60 °C.

Stability and Structural Characterization of Epitaxial NdNiO3 Films Grown by Pulsed Laser Deposition

2000 ◽  
Vol 658 ◽  
Author(s):  
Trong-Duc Doan ◽  
Cobey Abramowski ◽  
Paul A. Salvador
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Monoclinic Distortion

ABSTRACTThin films of NdNiO3 were grown using pulsed laser deposition on single crystal substrates of [100]-oriented LaAlO3 and SrTiO3. X-ray diffraction and reflectivity, scanning electron microscopy, and atomic force microscopy were used to characterize the chemical, morphological and structural traits of the thin films. Single-phase epitaxial films are grown on LaAlO3 and SrTiO3 at 625°C in an oxygen pressure of 200 mTorr. At higher temperatures, the films partially decompose to Nd2NiO4 and NiO. The films are epitaxial with the (101) planes (orthorhombic Pnma notation) parallel to the substrate surface. Four in-plane orientational variants exist that correspond to the four 90° degenerate orientations of the film's [010] with respect to the in-plane substrate directions. Films are observed to be strained in accordance with the structural mismatch to the underlying substrate, and this leads, in the thinnest films on LaAlO3, to an apparent monoclinic distortion to the unit cell.

Effects of Annealing on Pulsed Laser Deposited TiO2 Thin Films

2013 ◽  
Vol 446-447 ◽  
pp. 306-311 ◽  
Author(s):  
Sudhanshu Dwivedi ◽  
Somnath Biswas
Keyword(s):  
Thin Films ◽  
Pulsed Laser ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Si Substrates ◽  
Morphological Studies ◽  
Atomic Force ◽  
Deposited Films ◽  
Type Crystal

Mixed phase TiO2 thin films of rutile and anatase type crystal orientations were deposited on Si substrates by pulsed laser deposition (PLD) technique. When annealed at 800°C at 1 mbar oxygen pressure for 3 h, the deposited films transform into a single phase of rutile type. Structural and morphological studies of the as-deposited and annealed films were performed with X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), Raman spectroscopy, and atomic force microscopy (AFM). Photoluminescence (PL) spectroscopy was used for optical characterization of the annealed thin films.

MBE-grown NiyMg1-yO and ZnxMg1-xO Thin Films for Deep Ultraviolet Optoelectronic Applications

2009 ◽  
Vol 1201 ◽  
Author(s):  
Jeremy West Mares ◽  
Ryan Casey Boutwell ◽  
Matthew Thomas Falanga ◽  
Amber Scheurer ◽  
Winston Vaughan Schoenfeld
Keyword(s):  
Thin Films ◽  
Electrical Characterization ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Lattice Constants ◽  
Atomic Force ◽  
Zn Concentration ◽  
Deep Ultraviolet ◽  
Lattice Matched

AbstractWe report on the heteroepitaxial growth of high-quality single crystal cubic ZnxMg1-xO and NiyMg1-yO thin films by radio frequency oxygen plasma-assisted molecular beam epitaxy (RF-MBE). Film compositions over the ranges x = 0 to x = 0.65 and y = 0 to y = 1 have been grown on lattice-matched MgO (100) and characterized optically, morphologically, compositionally, and electrically. Both of these ternary materials are shown to have bandgaps which vary directly as a function of transition metal (Ni or Zn) concentration. Optical transmission measurements of NiyMg1-yO show the bandgap to shift continuously over the approximate range 3.5 eV (for NiO) to 4.81 eV (for y=0.075). Similarly, the bandgap of cubic ZnxMg1-xO is shifted from about 4.9 eV (for x = 0.65) to 6.25 eV (for x=0.12). Films exhibit good morphological quality and typical roughness of NiyMg1-yO films is 5 Å while that of ZnxMg1-xO is less than 15 Å, as measured by atomic force microscopy (AFM). X-ray diffraction (XRD) is employed to confirm crystal orientation and to determine the films' lattice constants. Film compositions are interrogated by Rutherford Backscattering (RBS) and electrical characterization is made by room-temperature Hall measurements.

Semiconducting YBCO Thin Films for Uncooled Terahertz Imagers

2008 ◽  
Vol 587-588 ◽  
pp. 273-277 ◽  
Author(s):  
Mattia Longhin ◽  
Alain J. Kreisler ◽  
Annick F. Dégardin
Keyword(s):  
Thin Films ◽  
Near Infrared ◽  
Electrical Characterization ◽  
X Ray Diffraction ◽  
Sensing Element ◽  
Force Microscopy ◽  
Research Activities ◽  
Atomic Force ◽  
Ybco Thin Films ◽  
Wide Range

The terahertz domain (500 GHz - 5 THz) has been object of unceasing research activities, due to the wide range of conceivable applications in these fields. This study focuses on the development of semiconducting YBa2Cu3O6+x (YBCO) thin films to be used as sensitive elements on future uncooled terahertz imagers working on a thermal principle. YBCO thin films have been hollow-cathode sputtered on MgO single-crystals under different conditions. Electrical and structural characterizations have then been carried out. The resistivity of the thin films and the temperature coefficient of resistance (TCR) have been determined. X-ray diffraction and atomic force microscopy analyses have then been performed. If compared with materials currently used as sensing element in commercial near-infrared imagers, electrical characterization shows values of the TCR comparable to amorphous silicon and almost two times better than VOx-compounds.

scholarly journals Analysis, Synthesis and Characterization of Thin Films of a-Si:H (n-type and p-type) Deposited by PECVD for Solar Cell Applications

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6349
Author(s):  
Abel Garcia-Barrientos ◽  
Jose Luis Bernal-Ponce ◽  
Jairo Plaza-Castillo ◽  
Alberto Cuevas-Salgado ◽  
Ariosto Medina-Flores ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Optical Band Gap ◽  
Synthesis And Characterization ◽  
Force Microscopy ◽  
The Third ◽  
Atomic Force ◽  
Uv Visible ◽  
P Type

In this paper, the analysis, synthesis and characterization of thin films of a-Si:H deposited by PECVD were carried out. Three types of films were deposited: In the first series (00 process), an intrinsic a-Si:H film was doped. In the second series (A1–A5 process), n-type samples were doped, and to carry this out, a gas mixture of silane (SiH4), dihydrogen (H2) and phosphine (PH3) was used. In the third series (B1–B5 process), p-type samples were doped using a mixture of silane (SiH4), dihydrogen (H2) and diborane (B2H6). The films’ surface morphology was characterized by atomic force microscopy (AFM), while the analysis of the films was performed by scanning electron microscopy (SEM), and UV–visible ellipsometry was used to obtain the optical band gap and film thickness. According to the results of the present study, it can be concluded that the best conditions can be obtained when the flow of dopant gases (phosphine or diborane) increases, as seen in the conductivity graphs, where the films with the highest flow of dopant gas reached the highest conductivities compared to the minimum required for materials made of a-Si:H silicon for high-quality solar cells. It can be concluded from the results that the magnitude of the conductivity, which increased by several orders, represents an important result, since we could improve the efficiency of solar cells based on a-Si:H.

A Structural Study of SrBi2Ta2O9 - Bi3TiNbO9 Ferroelectric Thin Films

1999 ◽  
Vol 596 ◽  
Author(s):  
E. Ching-Prado ◽  
W. Pérez ◽  
P. S. Dobalt ◽  
R. S. Katiyart ◽  
S. Tirumala ◽  
...  
Keyword(s):  
Thin Films ◽  
Remanent Polarization ◽  
Electrical Characterization ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Solution Deposition ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Metal Organic

AbstractThin films of ferroelectric (SrBi2Ta2O9)x(Bi3TiNbO9)1-x layered structure (for x = 0.0, 0.2, … 1.0) were prepared by a metal organic solution deposition method on Pt/TiO2/SiO2/Si substrates. Raman spectroscopy, X-ray diffraction, atomic force microscopy (AFM), and electrical characterization techniques were utilized to study the inclusion of SrBi2Ta2O9 (SBT) in the Bi3TiNbO9 (BTN) system. The Raman spectra show frequency shifts and broadening of modes as x increases from 0.0 to 0.4, which are related to the nature of Sr and Bi in the A-sites, and Ta, Ti, and Nb in the B-sites. Smooth surfaces without any cracks or defects were evidenced in each of these films by AFM. These images also indicate that the grain size in the films increases with increasing SBT content in the BTN compound. Electrical measurements show that the remanent polarization (Pr) and the coercive field (Ec) values in the x=0.0 film (2 μC/cm2 and 30 kV/cm, respectively) increase to 12.5 μC/cm2 and 125 kV/cm for x=0.6. A decrease in these parameters was found for higher compositions.

Synthesis and Characterization of ZnO Nanorods Using Molecular Beam Epitaxy

2012 ◽  
Vol 622-623 ◽  
pp. 919-924 ◽  
Author(s):  
M. Asghar ◽  
Khalid Mahmood ◽  
M. Yasin Raja ◽  
M.A. Hasan
Keyword(s):  
Raman Spectroscopy ◽  
Zno Nanorods ◽  
X Ray Diffraction ◽  
Type Conductivity ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Capacitance Voltage ◽  
Vertically Aligned

We present the study of the growth of ZnO nanorods on p-Si (100) using MBE. Various characterization techniques such as Fourier transform infra-red (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), Raman spectroscopy and capacitance – voltage (C-V) measurements were employed to analyze and assess the grown ZnO nanorods. AFM clearly demonstrated the growth of vertically aligned nanorods, however, they get diffused as the thickness of the layer is increased beyond 1 µm. C-V measurements in particular, justified p-n junction between Si/ZnO nanorods. The junction showed n-type conductivity with carrier concentration 1×1015cm-3. The source of this n-type conductivity was Zn-interstitials and the presence of Zn-interstitials was confirmed by EDAX and Raman spectroscopy. Experimental detail and results were presented that help in furtherance of our understanding of the material issues and its potential as required for the practical devices.

Low-Temperature Synthesis and Gas Sensing Properties of Anatase TiO2 Thin Films

2011 ◽  
Vol 492 ◽  
pp. 300-303
Author(s):  
Fu Jian Ren ◽  
Yi Sun ◽  
Liang Huang ◽  
Yun Han Ling ◽  
Jia You Feng
Keyword(s):  
Thin Films ◽  
Deposition Temperature ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Gas Sensing Properties ◽  
Gas Response

Crystalline anatase TiO2thin films were obtained on glass substrates at 60°C, 75°C and 90°C, respectively, by liquid phase deposition (LPD) method without subsequent heat treatment. X-ray diffraction (XRD), atomic force microscopy (AFM) and UV-Vis spectrophotometer were used to characterize the as-synthesized TiO2thin films. The H2sensing properties of the TiO2thin films based sensors were investigated. The results show that the gas sensors signal Ra/Rg (Ra: resistance in air, Rg: resistance in a sample gas) decreases with the increasing deposition temperature. The TiO2thin films obtained at deposition temperature of 60°C exhibited the maximum H2gas response at 350°C, and the magnitude of the sensor signal and the response time for 500ppm H2was 1.25 and 17s, respectively.

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