Optical and Electrical Properties of Some Organic Thin Films for Optoelectronic Applications

2011 ◽  
Vol 337 ◽  
pp. 426-429
Author(s):  
S.B. Chen ◽  
Zhi You Zhong
Keyword(s):  
Thin Films ◽  
Experimental Studies ◽  
Visible Region ◽  
Organic Thin Films ◽  
Optical Transmittance ◽  
Vacuum Sublimation ◽  
Semiconductor Thin Films ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Effective Carrier

Organic semiconductor thin films of bis-(2-methyl-8-quinolinolato)-4-(phenyl-phenolato) -aluminium-(III) (BAlq), N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)benzidine (NPB), and tris-(8- hydroxyquinoline) aluminum (Alq) were prepared by the vacuum sublimation technique. The optical properties in the UV-visible region of the thin films were investigated by optical transmittance and absorbance spectra. The optical energy gaps were obtained from direct allowed transitions at room temperature by Tauc’s law. The Urbach energy and the slope of Urbach edge were estimated by the Urbach-edges method, respectively. Furthermore, the current-voltage characteristics of organic thin films were analyzed, and the different slopes in the lower and higher voltage regions were observed. From the experimental studies, the effective carrier mobility, free carrier density, and electrical conductivity were also evaluated respectively.

Study on the Optical and Electrical Properties of Organic Semiconductor Thin Films for OLEDs

2012 ◽  
Vol 502 ◽  
pp. 106-110
Author(s):  
J.H. Gu ◽  
Z.Y. Zhong ◽  
X. He ◽  
C.Y. Yang ◽  
J. Hou
Keyword(s):  
Thin Films ◽  
Organic Semiconductor ◽  
Visible Region ◽  
Optical Transmittance ◽  
Vacuum Sublimation ◽  
Light Emitting ◽  
Semiconductor Thin Films ◽  
Current Voltage ◽  
Organic Semiconductor Materials ◽  
Hydroxy Quinoline

Organic semiconductor thin films of aluminum (III) bis(2-methyl-8-quninolinato)-4- phenylphenolate (BAlq), -naphthylphenylbiphenyl amine (NPB), and tris(8-hydroxy-quinoline) aluminum (AlQ) for organic light-emitting diodes (OLEDs) were deposited by the vacuum sublimation technique. The optical properties in the UV-visible region of the thin films were investigated by optical transmittance and absorption spectra. The band gaps were obtained from direct allowed transitions at room temperature by means of the Tauc plots. The Urbach energy and the slope of Urbach edge were evaluated, respectively according to the Urbach-edges method. The thin film devices of sandwich structure were fabricated using these organic semiconductor materials, in addition, the effective carrier mobility, free carrier density, and electrical conductivity of the thin films were calculated in terms of the measured current-voltage characteristics of the devices.

Magnetotransport Properties of MnGeAs2 Films

2017 ◽  
Vol 864 ◽  
pp. 116-120
Author(s):  
Yun Ki Kim ◽  
J.B. Ketterson
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Anomalous Hall Effect ◽  
Current Voltage ◽  
Spin Polarized ◽  
Current Voltage Characteristics ◽  
Small Change ◽  
P Type ◽  
Effective Carrier

MnGeAs2 thin films were successfully deposited on GaAs(100) substrate. The films exhibited room-temperature ferromagnetism with TC ~ 330 K, based on both magnetization and resistance measurements at temperatures from 5 to 370 K. The coercive fields at 5 and 300 K were 2100 and 50 Oe. The anomalous Hall effect was observed, suggesting the existence of spin polarized carriers in MnGeAs2 thin films. The magnetoresistance (MR) measurements showed very small change (~ 0.1% at 5 K) in resistance at low temperature. The MR value at 5 K was smaller than that (~ 9% at 305 K) at room temperature (305 K). Type of majority carriers in the films was determined to be n-type by Hall measurement above the transition temperature. The effective carrier density was 1.8´1020 cm-3. The diode current-voltage characteristics were shown in a hetero-junction MnGeAs2 film on a conducting p-type GaAs substrate.

Photocatalytic Degradation of Methylene Blue by NiO Thin Films under Solar Light Irradiation

2019 ◽  
Vol 56 ◽  
pp. 152-157 ◽  
Author(s):  
Abdelouahab Noua ◽  
Hichem Farh ◽  
Rebai Guemini ◽  
Oussama Zaoui ◽  
Tarek Diab Ounis ◽  
...  
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Sol Gel ◽  
Visible Region ◽  
Optical Transmittance ◽  
Dip Coating ◽  
Light Irradiation ◽  
Solar Light ◽  
Solar Light Irradiation

Nickel oxide (NiO) thin films were successfully deposited by sol-gel dip-coating method on glass substrates. The structural, morphological and optical properties in addition to the photocatalytic activity of the prepared films were investigated. The results show that the films have a polycrystalline NiO cubic structure with dense NiO grains and average optical transmittance in the visible region. The photocatalytic properties of the films were studied through the degradation of methylene blue and 89% of degradation was achieved for 4.5h of solar light irradiation exposure which indicates the capability of NiO photocatalytic activity.

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

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.

Photoconductivity of Nanocomposite MEH-PPV: TiO2 Thin Films

2011 ◽  
Vol 13 ◽  
pp. 87-92 ◽  
Author(s):  
M.S.P Sarah ◽  
F.S. Zahid ◽  
M.Z. Musa ◽  
U.M. Noor ◽  
Z. Shaameri ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Morphology ◽  
Spin Coating ◽  
Glass Substrate ◽  
Spin Coating Technique ◽  
Coating Technique ◽  
Current Voltage ◽  
Current Voltage Characteristics

The photoconductivity of a nanocomposite MEH-PPV:TiO2 thin film is investigated. The nanocomposite MEH-PPV:TiO2 thin film was deposited on a glass substrate by spin coating technique. The composition of the TiO2 powder was varied from 5 wt% to 20 wt% (with 5 wt% interval). The concentration of the MEH-PPV is given by 1 mg/1 ml. The current voltage characteristics were measured in dark and under illumination. The photoconductivity showed increment in value as the composition of the TiO2 is raised in the polymer based solution. The absorption showed augmentation as the amount of TiO2 is increased. The escalation of the current voltage is then supported by the results of surface morphology.

Characteristics of Indium Zinc Oxide Thin Films Deposited by Radio Frequency Reactive Magnetron Sputtering for Solar Cells Application

2007 ◽  
Vol 124-126 ◽  
pp. 999-1002 ◽  
Author(s):  
Han Na Cho ◽  
Jang Woo Lee ◽  
Su Ryun Min ◽  
Chee Won Chung
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Magnetron Sputtering ◽  
Radio Frequency ◽  
Visible Region ◽  
Film Surface ◽  
Optical Transmittance ◽  
Reactive Magnetron Sputtering ◽  
Reactive Magnetron ◽  
Indium Zinc Oxide

Indium zinc oxide (IZO) thin films were deposited on a glass substrate by radio frequency (rf) reactive magnetron sputtering method. As the rf power increased, the deposition rate and resistivity increased while the optical transmittance decreased owing to the increase of grain size. With increasing gas pressure, the resistivity increased and the transmittance decreased. Atomic force microscopy and scanning electron microscopy were employed to observe the film surface. The IZO films displayed a resistivity of 3.8 × 10-4 Ω cm and a transmittance of about 90% in visible region.

Ferroelectric Property and Microstructures of La-Doped Bi4Ti3O12 Thin Films

2013 ◽  
Vol 537 ◽  
pp. 114-117
Author(s):  
X.A. Mei ◽  
Rui Fang Liu ◽  
C.Q. Huang ◽  
J. Liu
Keyword(s):  
Thin Films ◽  
Hysteresis Loops ◽  
Differential Resistance ◽  
Rf Magnetron Sputtering ◽  
Layered Perovskite ◽  
Random Orientation ◽  
Si Substrates ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
La Doped

La-doped bismuth titanate (Bi4-xLaxTi3O12: BLT) and pure Bi4Ti3O12 (BIT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. For the samples with x=0.25 and 1.0 the current-voltage characteristics exhibited negative differential resistance behaviors and their P-V hysteresis loops were characterized by large leakage current, whereas for the samples with x=0.5 and 0.75 the current-voltage characteristics showed simple ohmic behaviors and their P-V hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BLT ceramic with x=0.75 were above 20μC/cm2 and 85KV/cm , respectively.

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