Photoferroelectric Effects of Undoped and Extrinsic Ion-Doped PZT Thin Films

ABSTRACTDeposition by aqueous acetate solution (DAAS) technique was used to synthesize undoped and 5 wt% Cr-, Mn-, Eu-, or Pr-doped Pb(Zr0.53Ti0.47O3 [PZT] thin films. The dopant was incorporated into PZT either in the precursor coating solution or via thermal diffusion into undoped PZT. X-ray diffraction shows that ion-doped PZT thin films on Pt<l 1 l>/Ti/SiO2/Si<100> (in particular, the Mn- and Eu- doped samples) display better crystallinity and smaller lattice parameters than those on sapphire substrates. The enhancement of photoconductivity at visible wavelengths measured by excitation photocurrent spectroscopy (EPS) goes as Cr-doped∼Mn-doped > Eu-doped ∼ Pr-doped. Only Mn-doped PZT perovskites have the band gap energy red-shifted to 360 nm from 330 nm. The space charge (or photovoltaic) field was estimated to be < 8 v when about 100 v was applied to ion-doped PZT thin films with 260 or 320 nm light. By using laser irradiation at selected wavelengths and switching the polarity of applied bias voltage, the expected changes in resistance (Ry) and remanent polarization (±Pr) states were observed in the P-E hysteresis loops. The possible applications of extrinsic ion-doped PZT thin films in optical memory devices are discussed.

Download Full-text

Preparation and Electrical Characteristics of (100), (111), and Randomly Oriented PZT Thin Films

MRS Proceedings ◽

10.1557/proc-361-445 ◽

1994 ◽

Vol 361 ◽

Author(s):

Chang Jung Kim ◽

Dae Sung Yoon ◽

Joon Sung Lee ◽

Chaun Gi Choi ◽

Won Jong Lee ◽

...

Keyword(s):

Thin Films ◽

Sol Gel ◽

Hysteresis Loops ◽

Test System ◽

Electrical Characteristics ◽

Pzt Thin Films ◽

Pole Figures ◽

Current Voltage ◽

Current Voltage Characteristics ◽

Drying Conditions

ABSTRACTThe (100), (111) and randomly oriented PZT thin films were fabricated on Pt/Ti/Coming 7059 glass using sol-gel method. The thin films having different orientation were fabricated by different drying conditions for pyrolysis. The preferred orientations of the PZT thin films were observed using XRD, rocking curves, and pole figures. The microstructures were investigated using SEM. The hysteresis loops and capacitance-voltage characteristics of the films were investigated using a standardized ferroelectric test system. The dielectric constant and current-voltage characteristics of the films were investigated using an impedance analyzer and pA meter, respectively. The films oriented in a particular direction showed superior electrical characteristics to the randomly oriented films.

Download Full-text

Band gap tuning and p to n-type transition in Mn-doped CuO nanostructured thin films

Journal of Semiconductors ◽

10.1088/1674-4926/43/1/012801 ◽

2022 ◽

Vol 43 (1) ◽

pp. 012801

Author(s):

R. Rahaman ◽

M. Sharmin ◽

J. Podder

Keyword(s):

Thin Films ◽

Band Gap ◽

Spray Pyrolysis Technique ◽

Band Gap Energy ◽

Dielectric Constants ◽

X Rays ◽

Electron Effective Mass ◽

Mn Doping ◽

Type Transition ◽

Mn Doped

Abstract Here we discuss the synthesis of copper (II) oxide (CuO) and manganese (Mn)-doped CuO thin films varying with 0 to 8 at% Mn using the spray pyrolysis technique. As-deposited film surfaces comprised of agglomerated spherical nanoparticles and a semi-spongy porous structure for 4 at% Mn doping. Energy dispersive analysis of X-rays confirmed the chemical composition of the films. X-ray diffraction spectra showed a polycrystalline monoclinic structure with the predominance of the ( 11) peak. Optical band gap energy for direct and indirect transitions was estimated in the ranges from 2.67–2.90 eV and 0.11–1.73 eV, respectively. Refractive index and static dielectric constants were computed from the optical spectra. Electrical resistivity of CuO and Mn-doped CuO (Mn:CuO) thin films was found in the range from 10.5 to 28.6 Ω·cm. The tiniest electron effective mass was calculated for 4 at% Mn:CuO thin films. P to n-type transition was observed for 4 at% Mn doping in CuO films. Carrier concentration and mobility were found in the orders of 1017 cm–3 and 10–1 cm2/(V·s), respectively. The Hall coefficient was found to be between 9.9 and 29.8 cm3/C. The above results suggest the suitability of Mn:CuO thin films in optoelectronic applications.

Download Full-text

Preparation and Characterization of Zn1-XMnxO Thin Films on SiO2 Substrates

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.560-561.820 ◽

2012 ◽

Vol 560-561 ◽

pp. 820-824

Author(s):

Yue Zhi Zhao ◽

Fei Xiong ◽

Guo Mian Gao ◽

Shi Jing Ding

Keyword(s):

Thin Films ◽

Rf Magnetron Sputtering ◽

Zno Films ◽

X Ray Diffraction ◽

Flat Surfaces ◽

Atomic Force ◽

Mn Content ◽

Doped Zno ◽

Mn Doped

Mn-doped ZnO thin films were prepared on SiO2substrates by using a radio-frequency(rf) magnetron sputtering in order to investigate structure and optical proprieties of the films. X-ray diffraction (XRD), Atomic force microscope (AFM) and UV-VIS spectrophotometry were employed to characterize the Mn-doped ZnO films. The results showed that the shape of the XRD spectrum was remarkably similar to that of the un-doped ZnO film; the film had mainly (002) peak, and indicate that the structure of the films was not disturbed by Mn-doped. The film had rather flat surfaces with the peak-to-tail roughness of about 25nm. Mn-doping changed the band gap of the films, which increased with the increase of the Mn content.

Download Full-text

Formation of ZnO Doped with Mn Thin Film by Electrodeposition and Magnetic Behaviour.

MRS Proceedings ◽

10.1557/proc-879-z7.17 ◽

2005 ◽

Vol 879 ◽

Author(s):

M. Abid ◽

C. Terrier ◽

J-P Ansermet ◽

K. Hjort

Keyword(s):

Thin Film ◽

Thin Films ◽

Room Temperature ◽

Magnetic Behaviour ◽

Spectroscopic Methods ◽

X Ray Diffraction ◽

X Ray ◽

Doped Zno ◽

Mn Doped ◽

Weak Ferromagnetic

AbstractFollowing the theory, ferromagnetism is predicted in Mn- doped ZnO, Indeed, ferromagnetism above room temperature was recently reported in thin films as well as in bulk samples made of this material. Here, we have prepared Mn doped ZnO by electrodeposition. The samples have been characterized by X-ray diffraction and spectroscopic methods to ensure that the dopants are substitutional. Some samples exhibit weak ferromagnetic properties at room temperature, however to be useful for spintronics this material need additional carriers provided by others means.

Download Full-text

Iron-Doped Lithium Tantalate Thin Films Deposited by Magnetron Sputtering: A Study of the Iron Role in the Structure and the Derived Magnetic Properties

Crystals ◽

10.3390/cryst10010050 ◽

2020 ◽

Vol 10 (1) ◽

pp. 50 ◽

Cited By ~ 2

Author(s):

Sergio David Villalobos Mendoza ◽

José Trinidad Holguín Momaca ◽

José Trinidad Elizalde Galindo ◽

Diana María Carrillo Flores ◽

Sion Federico Olive Méndez ◽

...

Keyword(s):

Thin Films ◽

Magnetron Sputtering ◽

Magnetic Hysteresis ◽

Hysteresis Loops ◽

Blocking Temperature ◽

Ferromagnetic Behavior ◽

Zero Field ◽

Cooling Curves ◽

X Ray Diffraction ◽

Field Cooling

Fe-doped LiTaO3 thin films with a low and high Fe concentration (labeled as LTO:Fe-LC and LTO:Fe-HC, respectively) were deposited by magnetron sputtering from two home-made targets. The dopant directly influenced the crystalline structure of the LiTaO3 thin films, causing the contraction of the unit cell, which was related to the incorporation of Fe3+ ions into the LiTaO3 structure, which occupied Li positions. This substitution was corroborated by Raman spectroscopy, where the bands associated with Li-O bonds broadened in the spectra of the samples. Magnetic hysteresis loops, zero-field cooling curves, and field cooling curves were obtained in a vibrating sample magnetometer. The LTO:Fe-HC sample demonstrates superparamagnetic behavior with a blocking temperature of 100 K, mainly associated with the appearance of Fe clusters in the thin film. On the other hand, a room temperature ferromagnetic behavior was found in the LTO:Fe-LC layer where saturation magnetization (3.80 kAm−1) and magnetic coercivities were not temperature-dependent. Moreover, the crystallinity and morphology of the samples were evaluated by X-ray diffraction and scanning electron microscopy, respectively.

Download Full-text

Excellent Room-Temperature Ferroelectricity in Mn-substituted BiFeO3 Thin Films Formed by Chemical Solution DepositionΨ

MRS Proceedings ◽

10.1557/proc-0933-g03-03 ◽

2006 ◽

Vol 933 ◽

Author(s):

Sushil Kumar Singh ◽

Hiroshi Ishiwara

Keyword(s):

Thin Films ◽

Leakage Current ◽

Lattice Structure ◽

Hysteresis Loops ◽

Secondary Phase ◽

Low Leakage ◽

Low Leakage Current ◽

Chemical Solutions ◽

Mn Substitution ◽

Mn Doped

AbstractMn-substituted BiFeO3 (BFO) thin films were formed by chemical solutions deposition on Pt/Ti/SiO2/Si(100) structures. Effects of the Mn-substitution on the structure and ferroelectricity of BFO films were examined. We found that the lattice structure of the film is sensitive to the Mn-substitution and the secondary phase is appears in 50% Mn-substituted BFO films. The leakage current were increased with the Mn-substitution. However, the 5% Mn-substituted BFO film shows low leakage current than undoped BFO films in a high electric field than 0.5 MV/cm. Due to the low leakage current in Mn-doped 3, 5 and 7% BFO films, the saturated P-E hysteresis loops with remanent polarization around 100 μC/cm2 were obtained at RT.

Download Full-text

Properties of CdS Thin Films Grown by Chemical Bath Deposition as a Function of Bath Temperature

Materials Science Forum ◽

10.4028/www.scientific.net/msf.609.243 ◽

2009 ◽

Vol 609 ◽

pp. 243-247 ◽

Cited By ~ 1

Author(s):

H. Moualkia ◽

S. Hariech ◽

M.S. Aida

Keyword(s):

Thin Films ◽

Optical Properties ◽

Band Gap ◽

Chemical Bath Deposition ◽

Bath Temperature ◽

Band Gap Energy ◽

X Ray Diffraction ◽

Glass Substrates ◽

Cds Thin Films ◽

Direct Band

The present work deals with the preparation and characterization of cadmium sulfur (CdS) thin films. These films are prepared by chemical bath deposition on the well cleaned glass substrates. The thickness of the samples was measured by using profilometer DEKTAK, structural and optical properties were studied by X-ray diffraction analysis, and UV-visible spectrophotometry. The optical properties of the films have been investigated as a function of temperature. The band gap energy and Urbach energy were also investigated as a function of temperature. From the transmittance data analysis the direct band gap ranges from 2.21 eV to 2.34 eV. A dependence of band gap on temperature has been observed and the possible raisons are discussed. Transmission spectra indicates a high transmission coefficient (75 %). Structural analysis revealed that the films showed cubic structure, and the crystallite size decreased at a higher deposition temperature.

Download Full-text

Tailoring of Multiferroic Properties of BiFeO3 Thin Films by Cation Substitution

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.442.102 ◽

2010 ◽

Vol 442 ◽

pp. 102-108 ◽

Cited By ~ 1

Author(s):

M.S. Awan ◽

A.S. Bhatti ◽

S. Qing ◽

C.K. Ong

Keyword(s):

Thin Films ◽

Single Phase ◽

Bottom Electrode ◽

X Ray Diffraction ◽

Free Surfaces ◽

X Ray ◽

Atomic Force ◽

Magnetization Saturation ◽

Multiferroic Bifeo3 ◽

Mn Doped

Mn-doped multiferroic BiFeO3 (BFMO) thin films were deposited on LaNiO3(LNO)/SrTiO3(STO)/Si(100) substrates by pulsed laser deposition (PLD) technique. X-ray diffraction (XRD) showed that films were bicrystalline single phase with (110) preferential orientation. Multiferroic top layer and oxide bottom electrode (LNO) epitaxially followed the buffer layer (STO). Oxygen partial pressure during deposition proved to be critical for phase formation, crystallinity and resistivity of the films. Atomic force microscopic (AFM) studies revealed the smooth, dense and crack free surfaces of the films. Cross-section view of the multilayers by field emission scanning electron microscope (FE-SEM) gave their thickness. Mn substitution resulted in the increase of magnetization saturation, coercive field and clarity of hysteresis loop. The magneto-electric (ME) effect was demonstrated by measuring the dielectric response in a varying magnetic field. Optimally deposited BFMO films show saturated P-E loop.

Download Full-text

Enhancement of Ferroelectricity and Magnetoelectric Effect of BiFeO3 Thin Films on Membrane Structure

MRS Proceedings ◽

10.1557/proc-0966-t03-13 ◽

2006 ◽

Vol 966 ◽

Author(s):

Seiji Nakashima ◽

Kwi-Young Yun ◽

Yoshitaka Nakamura ◽

Masanori Okuyama

Keyword(s):

Thin Film ◽

Thin Films ◽

Membrane Structure ◽

Remanent Polarization ◽

Hysteresis Loops ◽

X Ray Diffraction ◽

Multiferroic Bifeo ◽

Before And After ◽

Diffraction Peaks ◽

Ferroelectric Hysteresis

ABSTRACTMultiferroic BiFeO3 thin films have been prepared on Pt/TiO2/SiO2/thick (200 μm) and membrane (15 μm) Si substrate by pulsed laser deposition (PLD) to confirm the influence of stress from substrate. Si membrane was obtained by etching using reactive ion etching (RIE) until thickness is to be 15 μm. The X-ray diffraction peaks of BiFeO3 thin film on Pt/TiO2/SiO2/Si (15 μm) membrane substrate slightly shift to lower angles, compared to those on Pt/TiO2/SiO2/Si (200 μm) substrate. Ferroelectric hysteresis loops were also measured at 150 K before and after Si etching by RIE. The BiFeO3 thin film on the Pt/TiO2/SiO2/Si (15 μm) membrane structure shows remanent polarization (Pr) of 95 μC/cm2 for a maximum applied voltage of 18 V, which is larger than Pr = 71 μC/cm2 of BiFeO3 thin film on Pt/TiO2/SiO2/Si (200 μm) substrate at the same measurement conditions. Under magnetic field of 1.1 T, remanent polarization (Pr) of BiFeO3 thin film on Pt/TiO2/SiO2/Si (15 μm) membrane structure increased from 95 μC/cm2 to 101 μC/cm2 at 150 K due to stress relaxation of BiFeO3 thin film.

Download Full-text