scholarly journals Gamma Irradiation Effects on n-ZnSe/n-Si Isotype Heterojunctions

Silicon ◽  
2021 ◽  
Author(s):  
Indudhar Panduranga Vali ◽  
Rashmitha Keshav ◽  
M. Rajeshwari ◽  
K. S. Vaishnavi ◽  
M. G. Mahesha ◽  
...  

AbstractTo get an insight into the isotype heterojunction (IHJ) properties, the influence of gamma irradiation (GI) on the structural and electrical properties of n-ZnSe/n-Si has been presented. The ZnSe thin films were deposited onto the n-Si substrate by thermal evaporation technique. The X-ray diffraction (XRD) studies revealed the nanocrystalline nature of ZnSe thin films with prominent (111) orientation. The gamma irradiated samples displayed no crystallographic phase transformation up to 10 kGy irradiation doses. But noticeable and inconsistent modifications in the different lattice parameters were observed due to irradiation-induced effects. From the analysis of I-V characteristics, it has been found a similar trend in the variation of lattice mismatch, Schottky barrier height and interface trap parameter at different irradiation doses. Thus demonstrating the poor rectification properties of n-ZnSe/n-Si IHJs due to intrinsic and gamma-induced defects, and their role in the space charge limited conduction (SCLC) mechanism that significantly dominating over the thermionic emission (TE) mechanism across the barrier.

2021 ◽  
Author(s):  
Indudhar Panduranga Vali ◽  
Rashmitha Keshav ◽  
M Rajeshwari ◽  
K S Vaishnavi ◽  
M G Mahesha ◽  
...  

Abstract To get an insight into the isotype heterojunction (IHJ) properties, the influence of gamma irradiation (GI) on the structural and electrical properties of n-ZnSe/n-Si has been presented. The ZnSe thin films were deposited onto the n-Si substrate by thermal evaporation technique. The X-ray diffraction (XRD) studies revealed the nanocrystalline nature of ZnSe thin films with prominent (111) orientations. The gamma irradiated samples displayed no crystallographic phase transformation up to 10 kGy irradiation doses. But noticeable and inconsistent modifications in the different lattice parameters were observed due to irradiation-induced effects. From the analysis of I-V characteristics, it has been found a similar trend in the variation of lattice mismatch, Schottky barrier height and interface trap parameter at different irradiation doses. Thus demonstrating the poor rectification properties of n-ZnSe/n-Si IHJs due to intrinsic and gamma-induced defects, and their role in the space charge limited conduction (SCLC) mechanism that significantly dominating over the thermionic emission (TE) mechanism across the barrier.


2001 ◽  
Vol 666 ◽  
Author(s):  
Fumiaki Mitsugi ◽  
Tomoaki Ikegami ◽  
Kenji Ebihara ◽  
Jagdish Narayan ◽  
Alexander M. Grishin

ABSTRACTWe prepared colossal magnetoresistive La0.8Sr0.2MnO3 thin films on the MgO, SrTiO3 and LaAlO3 single crystal substrates using KrF excimer pulsed laser ablation technique. The structural and electrical properties of the La0.8Sr0.2MnO3 thin films which were strained by the lattice mismatch are reported. The in-plane lattice mismatch between the La0.8Sr0.2MnO3 and MgO, SrTiO3 and LaAlO3 substrates are -7.8 %, -0.5 % and +2.3 %, respectively. The X-ray diffraction spectra of the films exhibited c-axis orientation. In the case of the La0.8Sr0.2MnO3 / LaAlO3 thin films with thickness over 100 nm, the divided (00l) peaks were observed. The surface morphology and transport property of the strongly stressed La0.8Sr0.2MnO3 / LaAlO3 were different from those of La0.8Sr0.2MnO3 / MgO and La0.8Sr0.2MnO3 / SrTiO3thin films.


2011 ◽  
Vol 8 (1) ◽  
pp. 134-140
Author(s):  
Baghdad Science Journal

The paper reports the influence of annealing temperature under vacuum for one hour on the some structural and electrical properties of p-type CdTe thin films were grown at room temperature under high vacuum by using thermal evaporation technique with a mean thickness about 600nm. X-ray diffraction analysis confirms the formation of CdTe cubic phase at all annealing temperature. From investigated the electrical properties of CdTe thin films, the electrical conductivity, the majority carrier concentration, and the Hall mobility were found increase with increasing annealing temperatures.


2020 ◽  
Vol 38 (1) ◽  
pp. 174-180
Author(s):  
A.F. Qasrawi ◽  
Maram F. Taleb

AbstractIn this work, we report the effect of sandwiching of Au nanosheets on the structural and electrical properties of ZnSe thin films. The ZnSe films which are grown by the thermal evaporation technique onto glass and yttrium thin film substrates exhibit lattice deformation accompanied with lattice constant extension, grain size reduction and increased defect density upon Au nanosandwiching. The temperature dependent direct current conductivity analysis has shown that the 70 nm thick Au layers successfully increased the electrical conductivity by three orders of magnitude without causing degeneracy. On the other hand, the alternating current conductivity studies in the frequency domain of 10 MHz to 1800 MHz have shown that the alternating current conduction in ZnSe is dominated by both of quantum mechanical tunneling and correlated barrier hopping of electrons over the energy barriers formed at the grain boundaries. The Au nanosheets are observed to increase the density of localized states near Fermi level and reduce the average hopping energy by ~5 times. The conductivity, capacitance, impedance and reflection coefficient spectral analyses have shown that the nanosandwiching of Au between two layers of ZnSe makes the zinc selenide more appropriate for electronic applications and for applications which need microwave cavities.


2014 ◽  
Vol 11 (3) ◽  
pp. 1257-1260
Author(s):  
Baghdad Science Journal

In this work the effect of annealing temperature on the structure and the electrical properties of Bi thin films was studied, the Bi films were deposited on glass substrates at room temperature by thermal evaporation technique with thickness (0.4 µm) and rate of deposition equal to 6.66Å/sec, all samples are annealed in a vacuum for one hour. The X-ray diffraction analysis shows that the prepared samples are polycrystalline and it exhibits hexagonal structure. The electrical properties of these films were studied with different annealing temperatures, the d.c conductivity for films decreases from 16.42 ? 10-2 at 343K to 10.11?10-2 (?.cm)-1 at 363K. The electrical activation energies Ea1 and Ea2 increase from 0.031 to 0.049eV and from 0.096 to 0. 162 eV with increasing of annealing temperature from 343K to 363K, respectively. Hall measurements showed that all the films are p-type.


2016 ◽  
Vol 12 (3) ◽  
pp. 4394-4399
Author(s):  
Sura Ali Noaman ◽  
Rashid Owaid Kadhim ◽  
Saleem Azara Hussain

Tin Oxide and Indium doped Tin Oxide (SnO2:In) thin films were deposited on glass and Silicon  substrates  by  thermal evaporation technique.  X-ray diffraction pattern of  pure SnO2 and SnO2:In thin films annealed at 650oC and the results showed  that the structure have tetragonal phase with preferred orientation in (110) plane. AFM studies showed an inhibition of grain growth with increase in indium concentration. SEM studies of pure  SnO2 and  Indium doped tin oxide (SnO2:In) ) thin films showed that the films with regular distribution of particles and they have spherical shape.  Optical properties such as  Transmission , optical band-gap have been measured and calculated.


2001 ◽  
Vol 688 ◽  
Author(s):  
Rasmi R. Das ◽  
W. Pérez ◽  
P. Bhattacharya ◽  
Ram. S. Katiyar

AbstractWe have grown SrBi2Ta2O9 (SBT) thin films on various bottom electrodes such as Pt/TiO2/SiO2/Si (Pt) and LaNiO3/Pt/TiO2/SiO2/Si (LNO) substrates. The substrate temperature and oxygen pressure for the SBT film was maintained at 500 °C and 200 mTorr. As-grown films were post-annealed at a temperature of 800 °C. X-ray diffraction studies revealed that as-grown films were amorphous and crystallized to single phase after annealing. The difficulty of obtaining lowest Raman modes of SBT on platinized silicon substrate was overcome by using conducting oxide electrodes. Films grown on platinized silicon showed maximum value of remanent polarization (2Pr ∼ 21.5 μC/cm2) with coercive field (Ec) of ∼ 67 kV/cm. The degradation of ferroelectric properties of the films was observed with the introduction of 50 nm conducting LaNiO3 electrode at the interface of Pt and SBT film, which was attributed to high resistivity of the oxide electrode layers. Leakage current density was studied with the consideration of the Schottky emission model. The barrier height of the films grown on Pt and LNO were estimated to be 1.27 eV and 1.12 eV, respectively. The reduction of barrier height was attributed to the lower work function of the LNO electrode.


2013 ◽  
Vol 665 ◽  
pp. 254-262 ◽  
Author(s):  
J.R. Rathod ◽  
Haresh S. Patel ◽  
K.D. Patel ◽  
V.M. Pathak

Group II-VI compounds have been investigated largely in last two decades due to their interesting optoelectronic properties. ZnTe, a member of this family, possesses a bandgap around 2.26eV. This material is now a day investigated in thin film form due to its potential towards various viable applications. In this paper, the authors report their investigations on the preparation of ZnTe thin films using vacuum evaporation technique and their structural and optical characterizations. The structural characterization, carried out using an X-ray diffraction (XRD) technique shows that ZnTe used in present case possesses a cubic structure. Using the same data, the micro strain and dislocation density were evaluated and found to be around 1.465×10-3lines-m2and 1.639×1015lines/m2respecctively. The optical characterization carried out in UV-VIS-NIR region reveals the fact that band gap of ZnTe is around 2.2eV in present case. In addition to this, it was observed that the value of bandgap decreases as the thickness of films increases. The direct transitions of the carries are involved in ZnTe. Using the data of UV-VIS-NIR spectroscopy, the transmission coefficient and extinction coefficient were also calculated for ZnTe thin films. Besides, the variation of extinction coefficient with wavelength has also been discussed here.


2019 ◽  
Vol 14 (29) ◽  
pp. 55-72
Author(s):  
Bushra A. Hasan

Alloys of InxSe1-x were prepared by quenching technique withdifferent In content (x=10, 20, 30, and 40). Thin films of these alloyswere prepared using thermal evaporation technique under vacuum of10-5 mbar on glass, at room temperature R.T with differentthicknesses (t=300, 500 and 700 nm). The X–ray diffractionmeasurement for bulk InxSe1-x showed that all alloys havepolycrystalline structures and the peaks for x=10 identical with Se,while for x=20, 30 and 40 were identical with the Se and InSestandard peaks. The diffraction patterns of InxSe1-x thin film showthat with low In content (x=10, and 20) samples have semicrystalline structure, The increase of indium content to x=30decreases degree of crystallinity and further increase of indiumcontent to x=40 leads to convert structure to amorphous. Increase ofthickness from 300 to 700nm increases degree of crystallinity for allindium content. Transmittance measurements were used to calculaterefractive index n and the extinction coefficient k using Swanepole’smethod. The optical constants such as refractive index (n), extinctioncoefficient (k) and dielectric constant (εr, εi) increases for low indiumcontent samples and decreases for high indium content samples,while increase of thickness increases optical constants for all xvalues. The oscillator energy E0, dispersion energy Ed, and otherparameters have been determined by Wemple - DiDomenico singleoscillator approach.


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