Habibah Zulkefle

Enhancement in Dielectric Constant and Structural Properties of Sol-Gel Derived MgO Thin Film using ZnO/MgO Multilayered Structure

High dielectric constant, low porosity and nano-dimension particle of single layer magnesium oxide, MgO and multilayer ZnO/MgO were synthesized at different MgO solution molar concentration by the simple chemical solution technique. The MgO molar concentration was found to alter the properties of both single and multilayer films. Observation reveals the surface morphology change form uniform to agglomerate and porous structure with corresponding increase in molar concentration. The increment in particle size and the formation of agglomerated particle were observed by FESEM (JEOL JSM-J600F). The best prepared dielectric film for both single and multilayer is the film that deposited using 0.4 molar concentration MgO solution due to its high dielectric constant, uniform film, and the particle is in nanometer dimension with nonorod like structure.

Influence of Doping Concentration on Dielectric, Optical, and Morphological Properties of PMMA Thin Films

PMMA thin films were deposited by sol gel spin coating method on ITO substrates. Toluene was used as the solvent to dissolve the PMMA powder. The PMMA concentration was varied from 30 ~ 120 mg. The dielectric properties were measured at frequency of 0 ~ 100 kHz. The dielectric permittivity was in the range of 7.3 to 7.5 which decreased as the PMMA concentration increased. The dielectric loss is in the range of 0.01 ~ –0.01. All samples show dielectric characteristics which have dielectric loss is less than 0.05. The optical properties for thin films were measured at room temperature across 200 ~ 1000 nm wavelength region. All samples are highly transparent. The energy band gaps are in the range of 3.6 eV to 3.9 eV when the PMMA concentration increased. The morphologies of the samples show that all samples are uniform and the surface roughness increased as the concentration increased. From this study, it is known that, the dielectric, optical, and morphology properties were influenced by the amount of PMMA concentration in the solution.

Effect of Solvent on the Dielectric Properties of Nanocomposite Poly(methyl methacrylate)-Doped Titanium Dioxide Dielectric Films

A poly(methyl methacrylate)-doped titanium dioxide (PMMA:TiO2) nanocomposite film was obtained by spin coating the nanocomposite solution onto a silicon substrate. The nanocomposite solutions were prepared by dissolving the PMMA and TiO2 nanopowder in three different types of organic solvent, namely, toluene, tetrahydrofuran (THF), and acetone. We found that the dielectric properties of the PMMA:TiO2 nanocomposite are dependent on the type of solvent used. The dielectric properties measured at a frequency of 1 kHz showed that acetone gives the highest dielectric constant and capacitance compared with toluene and THF. Toluene gives the lowest dielectric loss among the three. The topography and roughness of the PMMA:TiO2 nanocomposite indicate that a particular solvent results in a different kind of surface morphology.

Effect of molar concentration on electrically resistive lead titanate thin films by simple sol-gel method

Lead titanate thin films were successfully prepared using a simple sol-gel method. In the present study extra Pb excess was not taken into consideration in such a way that the ratio of Pb:Ti is 1:1. Different molar concentration (0.1, 0.2, 0.3, 0.4, and 0.5) involved in this study and it was found that the solutions increased in acidic level by the increment of molar concentration that being measured by pH and conductivity meter (JENWAY-3540). It also indicated that the solutions were electrically resistive at low concentration which might due to the existence of lead and oxygen ionic bonding. The solutions were then deposited onto cleaned glass substrate by spin coating technique indeed to have better thin film homogeneity at room temperature. The prepared thin films were characterized on electrical property considering the resistivity measured by solar simulator (BUKOH KEIKI EP-2000). After that structural and physical property of thin films were observed by atomic force microscopy (Park System, XE-100).

Different surface morphology of annealed PVDF-TrFE thin films and the effect on its ferroelectric properties

The different morphology of 250 nm PVDF-TrFE (70:30 mol%) thin films were observed in relation to its ferroelectricity. The annealing temperatures were varied from solvent evaporation (Ts), Curies transition (Tc), up to melting temperature (Tm). It was found that the annealing process promoted the development of elongated crystallite structure also known as ferroelectric crystal, which significantly improved the ferroelectric properties of PVDF-TrFE (70:30 mol%) thin films. However, the presence of nanoscale separations on the thin film annealed over Tm (AN160) suggested high possibility of defects, and hence a reduction in ferroelectric properties of thin films.

Ferroelectric characteristics of ZnO/MgO-based organic capacitor

Magnesium oxide, MgO with nanometre dimension particles size (36 to 73 nm) was successfully deposited on cleaned glass substrate. The drying temperatures were varied from 100 to 300°C and the dielectrics behaviour was investigated. From the results, it was revealed that variation of nano-MgO films properties obtained by changing the drying temperature. Nano-MgO film dried at 200°C was found to be a good dielectric layer due to it structural properties that resulted in the enhancement of relative permittivity value. The electrical properties shows better in dielectric layer characteristic where the resistivity was found to be 12.8 × 104 Ω.cm with leakage current density of 10−9 A.cm−2. The ZnO/MgO-based organic capacitor was fabricated and the remnant polarisation obtained was in range of 59 to 69 mC/m2 with capacitance value of 40 pF.

Thickness Dependency on Dielectric Property of Lead Titanate Thin Film

Previous studies have shown that lead titanate (PbTiO3) with its full potential brings out the ferroelectric property provided by its perovskite structure. It was predicted that from origination to become a modified lead titanate is most preferable, i.e. lead zirconium titanate (PZT). In the present study, PbTiO3 thin films were made through a simple sol-gel method by using spin coating technique. The deposition of thin films was at constant rate, 100rpm/s and took about 25s to complete. The fabricated thin films were then annealed at different temperature. After that, the films thickness measurement was taken by surface profiler (KLA Tencor) and characterization on dielectric property comprised at different anneal temperature. This feature indicates the power loss that will be taken into account under ac condition. The measurement of thin films was executed at 1Hz to 1MHz by using impedance spectroscopy analyzer (Solartron S1 1260A-1296) and electrical part was measured by solar simulator (BUKOH KEIKI EP-2000).

Molar concentration effect on MgO thin films properties

Magnesium Oxide, MgO is inorganic material with wide band gap (7.8eV) and suitable to be used as dielectric layer. Due to its chemical and structural properties, MgO also can be used as template to prepare ferroelectric thin film [1–3]. In this work, MgO thin films with different molar concentration from 0.1M to 1M were prepared using sol-gel spin coating technique. Magnesium acetate tetrahydrate, ethanol and nitric acid were used as precursor, solvent and stabilizer respectively. The MgO thin films were deposited on the glass substrate and subjected to electrical and structural characterizations. Both electrical and structural characterizations were performed using two point probes (BUKOH KEIKI-EP2000), surface profiler (Veeco) and atomic force microscope respectively. The experimental results show that the thin films resistivity increased from 5.09 ×103 Ω.cm to 2.33 ×104 Ω.cm as the precursor molar concentration increased. The MgO films with 0.4M was observed to be the best MgO films to be used as dielectric layer due to its electrical and structural properties which are uniform, non-porous and small particle size around 43nm.

Chemical Solution-Based Synthesis of Nano-Magnesium Oxide Dielectrics

The effect of MgO nano-filler loading to the dielectric layer properties of nano-Mgo films has been studied. By using FESEM, the particle size of nano-MgO dielectrics was found in nanometer dimension with the range of 42 to 92 nm. The addition of MgO nano-filler resulted in surface modification in which it lead to the changes in dielectrics properties. From impedance analysis it shows that there were only small changes in relative permittivity value since the filler and the matrix were the same material. The result also revealed that the dielectrics with 1 wt% filler loading has good electrical properties while dielectrics 2 wt% filler loading was very uniform and compact.

Electrical Characterization of Metal Insulator Semiconductor Using ZnO Low Deposition Temperature as Semiconductor Layer

We report on the influence of the low deposition temperature of ZnO as semiconductor layer on the electrical characteristics of metal-insulator-semiconductor (MIS) structures. The ZnO films were deposited by radio frequency (RF) magnetron sputtering with variation of temperature from 40°C, 60°C, 80°C, 100°C and 120°C. PMMA were used as insulator layer in the MIS structures. It is found that the ZnO films grown at 120°C has better crystallinity compared to other temperature. I-V characteristics results shown that the different deposition temperature of ZnO films affect the performance of MIS.