TEMPERATURE-DEPENDENT MODIFICATIONS OF Ag/SiO2/p-Si SCHOTTKY CONTACTS FORMED AT 20 K

2010 ◽  
Vol 09 (03) ◽  
pp. 135-138
Author(s):  
A. ALI ◽  
M. YASAR ◽  
F. NASIM ◽  
A. S. BHATTI
Keyword(s):  
Grain Size ◽  
Barrier Height ◽  
Ideality Factor ◽  
Thermal Evaporation ◽  
Schottky Contacts ◽  
Temperature Dependent ◽  
Ideal Behavior ◽  
Annealing Temperatures ◽  
Average Grain Size ◽  
Increasing Temperature

The Schottky contacts of Ag/SiO2 /p- Si were fabricated by thermal evaporation at 20 K. The effect of annealing temperatures varying from 373 to 773 K on the morphology and electrical properties of these contacts was investigated. The average grain size increased while the density of grains decreased with increasing temperature. Ideality factor initially observed was as high as 4.15 with a low barrier height of 0.04 eV for contact grown at 20 K. Annealing resulted in shift of ideality factor and barrier height towards ideal behavior. Thus, it is demonstrated that Ag/SiO2 /p- Si contacts grown at low temperature can be modified by annealing.

Analysis of temperature-dependent Schottky barrier parameters of Cu–Au Schottky contacts to n-InP

2012 ◽  
Vol 90 (1) ◽  
pp. 73-81 ◽  
Author(s):  
V. Lakshmi Devi ◽  
I. Jyothi ◽  
V. Rajagopal Reddy
Keyword(s):  
Schottky Barrier ◽  
Barrier Height ◽  
Gaussian Distribution ◽  
Ideality Factor ◽  
Thermionic Emission ◽  
Schottky Contacts ◽  
Temperature Dependent ◽  
Semiconductor Interface ◽  
Zero Bias ◽  
Barrier Heights

In this work, we have investigated the electrical characteristics of Au–Cu–n-InP Schottky contacts by current–voltage (I–V) and capacitance–voltage (C–V) measurements in the temperature range 260–420 K in steps of 20 K. The diode parameters, such as the ideality factor, n, and zero-bias barrier height, Φb0, have been found to be strongly temperature dependent. It has been found that the zero-bias barrier height, Φb0(I–V), increases and the ideality factor, n, decreases with an increase in temperature. The forward I–V characteristics are analyzed on the basis of standard thermionic emission (TE) theory and the assumption of gaussian distribution of barrier heights, due to barrier inhomogeneities that prevail at the metal–semiconductor interface. The zero-bias barrier height Φb0 versus 1/2kT plot has been drawn to obtain the evidence of a gaussian distribution of the barrier heights. The corresponding values are Φb0 = 1.16 eV and σ0 = 159 meV for the mean barrier height and standard deviation, respectively. The modified Richardson plot has given mean barrier height, Φb0, and Richardson constant, A**, as 1.15 eV and 7.34 Acm−2K−2, respectively, which is close to the theoretical value of 9.4 Acm−2K−2. Barrier heights obtained from C–V measurements are higher than those obtained from I–V measurements. This inconsistency between Schottky barrier heights (SBHs) obtained from I–V and C–V measurements was also interpreted. The temperature dependence of the I–V characteristics of the Au–Cu–n-InP Schottky diode has been explained on the basis of TE mechanism with gaussian distribution of the SBHs.

scholarly journals MORPHOLOGICAL AND ELECTRICAL PROPERTIES OF CDSE THIN FILMS PREPARED BY THERMAL EVAPORATION TECHNIQUE

2021 ◽  
Vol 03 (01) ◽  
pp. 39-44
Author(s):  
Asmaa Natiq Mohammed ALI
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Electrical Properties ◽  
Thermal Evaporation ◽  
Mean Free Path ◽  
Thermal Evaporation Technique ◽  
Annealing Temperatures ◽  
Average Grain Size ◽  
Evaporation Technique ◽  
Different Thickness

In this work , CdSe thin films with different thickness (100 and 200) nm have been prepared at RT by thermal evaporation technique on glass substrate under vacuum of 10-5 mbar. These films have been annealed to different annealing temperatures (423,473 and523) K. The morphology structure of the films has been examined using atomic force microscope (AFM) analysis. AFM measurements showed that the average grain size values of CdSe thin films decrease with increasing of annealing temperatures from (RT-523K). While the average grain size values increase with increasing thickness. The electrical properties of these films were studied with different thickness and annealing temperature. The d.c. conductivity for all deposited films decreases with increases of annealing temperatures. The electrical activation energies Ea1 and Ea2 found to decrease with increasing of thicknesses. While increase with increasing of annealing temperatures. From Hall effect result, it is found that the carriers concentration increase with increasing of annealing temperatures. While decrease with increasing of thickness. Hall mobility, drift velocity, carrier life time and mean free path decrease with increasing of thickness and annealing temperatures

Current-Voltage and Capacitance-Voltage Characteristics of Pd Schottky Diodes Fabricated on ZnO Grown along Zn- and O-Faces

2013 ◽  
Vol 313-314 ◽  
pp. 270-274
Author(s):  
M. Faisal ◽  
M. Asghar ◽  
Khalid Mahmood ◽  
Magnus Willander ◽  
O. Nur ◽  
...  
Keyword(s):  
Barrier Height ◽  
Ideality Factor ◽  
Doping Concentration ◽  
Series Resistance ◽  
Schottky Diodes ◽  
Thermionic Emission ◽  
Temperature Dependent ◽  
Current Voltage ◽  
Capacitance Voltage ◽  
Increasing Temperature

Temperature dependent current-voltage (I-V) and capacitance-voltage (C-V) measurements were utilized to understand the transport mechanism of Pd Schottky diodes fabricated on Zn- and O-faces of ZnO. From I-V measurements, in accordance with the thermionic emission mechanism theory, it was found that the series resistance Rsand the ideality factor n were strongly temperature dependent that decreased with increasing temperature for both the faces (Zn and O-face) of ZnO revealing that the thermionic emission is not the dominant process. The barrier height øB(I-V)increased with increasing temperature for both faces. The measured values of ideality factor, barrier height and series resistance for Zn- and O-faces at room temperature were 4.4, 0.60 eV, 217 Ω and 2.8, 0.49 eV, 251 Ω respectively. The capacitance-voltage (C–V) measurements were used to determine the doping concentration Nd, the built-in-potential Vbi, and the barrier height øB(C-V). The doping concentration was found to be decreased with increasing depth. The barrier height øB(C-V)calculated for O-polar and Zn-polar faces decreases with increasing temperature. The values of barrier height øB(C-V)determined from C-V measurements were found higher than the values of barrier height øB(I-V). Keeping in view the calculated values of ideality factor, barrier height, and series resistance shows that O-polar face is qualitatively better than Zn-polar face.

ATOMIC FORCE MICROSCOPY AND XRD ANALYSIS OF SILVER FILMS DEPOSITED BY THERMAL EVAPORATION

2006 ◽  
Vol 20 (02) ◽  
pp. 217-231 ◽  
Author(s):  
MUHAMMAD MAQBOOL ◽  
TAHIRZEB KHAN
Keyword(s):  
Atomic Force Microscopy ◽  
Grain Size ◽  
Surface Characterization ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Xrd Analysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Average Grain Size ◽  
20 Nm

Thin films of pure silver were deposited on glass substrate by thermal evaporation process at room temperature. Surface characterization of the films was performed using X-ray diffraction (XRD) and atomic force microscopy (AFM). Thickness of the films varied between 20 nm and 72.8 nm. XRD analysis provided a sharp peak at 38.75° from silver. These results indicated that the films deposited on glass substrates at room temperature are crystalline. Three-dimension and top view pictures of the films were obtained by AFM to study the grain size and its dependency on various factors. Average grain size increased with the thickness of the deposited films. A minimum grain size of 8 nm was obtained for 20 nm thick films, reaching 41.9 nm when the film size reaches 60 nm. Grain size was calculated from the information provided by the XRD spectrum and averaging method. We could not find any sequential variation in the grain size with the growth rate.

Electrical Properties of Inhomogeneous Pt/GaN Schottky Barrier

2008 ◽  
Vol 600-603 ◽  
pp. 1341-1344 ◽  
Author(s):  
Fabrizio Roccaforte ◽  
Ferdinando Iucolano ◽  
Filippo Giannazzo ◽  
Salvatore di Franco ◽  
Valeria Puglisi ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Temperature Dependence ◽  
Schottky Barrier ◽  
Barrier Height ◽  
Ideality Factor ◽  
Schottky Contacts ◽  
Electrical Behavior ◽  
Atomic Force ◽  
Current Voltage ◽  
Local Current

In this work, the electrical properties of Pt/GaN Schottky contacts were studied. The temperature dependence of the barrier height and ideality factor, and the low experimental value of the Richardson’s constant, were discussed considering the formation of an inhomogenous Schottky barrier. Local current-voltage measurements on Pt/GaN contact, performed with a conductive atomic force microscope, demonstrated a Gaussian distribution of the local barrier height values and allowed to monitor the degree of inhomogeneity of the barrier. The presence of defects, terminating on the bare GaN surface, was correlated with the electrical behavior of the inhomogeneous barrier.

Influence of CeO2-Doping on the Electrical Properties of ZnO-Bi2O3-Based Varistor Ceramics

2016 ◽  
Vol 697 ◽  
pp. 262-266
Author(s):  
Zhan Chuan Cao ◽  
Liao Ying Zheng ◽  
Li Hong Cheng ◽  
Tian Tian ◽  
Guo Rong Li
Keyword(s):  
Grain Size ◽  
Phase Composition ◽  
Detection Limit ◽  
Electrical Properties ◽  
Barrier Height ◽  
Nonlinear Coefficient ◽  
Donor Concentration ◽  
Average Grain Size ◽  
Doped Zno ◽  
Density Of Interface States

The microstructure and electrical properties of CeO2-doped ZnO-Bi2O3-based varistors were investigated for different amounts of the dopant. The phase composition of CeO2-doped samples was similar to the undoped samples. Ce mainly segregated at the grain boundaries within the EDS detection limit. The average grain size decreased from 7.3 to 6.7 μm and the breakdown voltage increased from 438 to 501 V/mm when the content of CeO2 ranged from 0 to 0.2 mol%. The nonlinear coefficient increased from 38 to 51 when the content of CeO2 increased from 0 to 0.1 mol%., but the further doping caused it to decrease up to 44 at 0.2mol%. The leakage current decreased from 1 to 0.4 μA/cm2 when the content of CeO2 ranged from 0 to 0.1 mol%. Then it increased to 0.7 μA/cm2 at 0.2 mol%. The density of interface states, the barrier height and the donor concentration increased when the content of CeO2 ranged from 0 to 0.1 mol%, but decreased at 0.2 mol%. Hence, when the content ranges from 0 to 0.1 mol%, CeO2 acts as a donor and can improve the electrical properties.

Temperature dependent ideality factor and barrier height of Ni/n-GaAs/In Schottky diodes

2012 ◽  
Vol 98 ◽  
pp. 6-11 ◽  
Author(s):  
Durmuş Ali Aldemir ◽  
Ali Kökce ◽  
Ahmet Faruk Özdemir
Keyword(s):  
Barrier Height ◽  
Ideality Factor ◽  
Schottky Diodes ◽  
Temperature Dependent

Surface Preparation of 6H-SiC Substrates by Electron Beam Annealing

2005 ◽  
Vol 483-485 ◽  
pp. 725-728 ◽  
Author(s):  
Oleg A. Agueev ◽  
Sergey P. Avdeev ◽  
Alexander M. Svetlichnyi ◽  
Raisa V. Konakova ◽  
Victor V. Milenin ◽  
...  
Keyword(s):  
Electron Beam ◽  
Surface Morphology ◽  
Barrier Height ◽  
Sheet Resistance ◽  
Ideality Factor ◽  
Surface Preparation ◽  
Schottky Contacts ◽  
The Mean ◽  
Surface Sheet

An effect of electron beam annealing (EBA) on both surface morphology and characteristics of test Ti/n-6H-SiC contacts was investigated. It was found that the mean roughness of the n-6H-SiC surface decreased from 3.43 nm to 1.35 nm and the surface sheet resistance increased from 3.1 to 4.0 Ω/sq after EBA. The Ti/n-6H-SiC contacts formed on substrates after EBA exhibited ohmic properties, while the same contacts formed on the un-annealed samples were Schottky contacts with the barrier height of 0.63 eV and ideality factor of 1.92.

scholarly journals Sintering Temperature, Frequency, and Temperature Dependent Dielectric Properties of Na0.5Sm0.5Cu3Ti4O12 Ceramics

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4805
Author(s):  
Hicham Mahfoz Kotb ◽  
Hassan A. Khater ◽  
Osama Saber ◽  
Mohamad M. Ahmad
Keyword(s):  
Grain Size ◽  
Dielectric Properties ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Low Dielectric ◽  
Average Grain Size ◽  
Conventional Sintering ◽  
Calculated Activation Energy

NSCTO (Na0.5Sm0.5Cu3Ti4O12) ceramics have been prepared by reactive sintering solid-state reaction where the powder was prepared from the elemental oxides by mechanochemical milling followed by conventional sintering in the temperature range 1000–1100 °C. The influence of sintering temperature on the structural and dielectric properties was thoroughly studied. X-ray diffraction analysis (XRD) revealed the formation of the cubic NSCTO phase. By using the Williamson–Hall approach, the crystallite size and lattice strain were calculated. Scanning electron microscope (SEM) observations revealed that the grain size of NSCTO ceramics is slightly dependent on the sintering temperature where the average grain size increased from 1.91 ± 0.36 μm to 2.58 ± 0.89 μm with increasing sintering temperature from 1000 °C to 1100 °C. The ceramic sample sintered at 1025 °C showed the best compromise between colossal relative permittivity (ε′ = 1.34 × 103) and low dielectric loss (tanδ = 0.043) values at 1.1 kHz and 300 K. The calculated activation energy for relaxation and conduction of NSCTO highlighted the important role of single and double ionized oxygen vacancies in these processes.

scholarly journals Development and Characterization of Titanium Dioxide Ceramic Substrates with High Dielectric Permittivities

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 386 ◽  
Author(s):  
Antonio E. Freitas ◽  
Taise M. Manhabosco ◽  
Ronaldo J. C. Batista ◽  
Alan K. Rêgo Segundo ◽  
Humberto X. Araújo ◽  
...  
Keyword(s):  
Grain Size ◽  
Titanium Dioxide ◽  
Rutile Phase ◽  
Solid State Reactions ◽  
Relative Dielectric Permittivity ◽  
Dielectric Parameters ◽  
Ceramic Substrates ◽  
Average Grain Size ◽  
High Dielectric ◽  
Increasing Temperature

Titanium dioxide substrates have been synthesized by means of solid-state reactions with sintering temperatures varying from 1150 °C up to 1350 °C. X-ray diffraction and scanning electron microscopy (SEM) where employed to investigate the crystal structure, grain size and porosity of the resulting samples. The obtained ceramics are tetragonal (rutile phase) with average grain sizes varying from 2.94 µm up to 5.81 µm. The average grain size of samples increases with increasing temperature, while the porosity decreases. The effect of microstructure on the dielectric properties has been also studied. The reduction of porosity of samples significantly improves the dielectric parameters (relative dielectric permittivity and loss tangent) in comparison to those of commercial substrates, indicating that the obtained ceramic substrates could be useful in the miniaturization of telecommunication devices.

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