Thermoelectric and Structural Properties of Bi1-xTe1+x Thin Films on CdTe(111)

1998 ◽  
Vol 545 ◽  
Author(s):  
Yunki Kim ◽  
Sunglae Cho ◽  
Antonio DiVenere ◽  
George K. Wong ◽  
Jerry R. Meyer ◽  
...  

AbstractThin films of the hexagonal phase of Bi1-xTe1+x have been grown on CdTe(111) substrates using molecular beam epitaxy (MBE). Analysis of X-ray diffraction patterns (θ-2θ scans and rocking curves) of the films shows that their crystallinity depends upon the compositional deviation from stoichiometric BiTe. Measurements of the temperature-dependent thermoelectric power (TEP) of the films reveals that compositional changes cause the TEP to vary from electron dominant (n-type) to hole dominant (p-type), implying their possible application as a thermoelectric cooler or power generator. Measurements of the temperature-dependent resistivity of the films were conducted, and the analysis shows semimetallic behavior. These results demonstrate that Bi1-xTe1+xis an appropriate model system to study the dependencies of thermoelectric and structural properties on binary composition.

2013 ◽  
Vol 341-342 ◽  
pp. 129-133
Author(s):  
Juan Qin ◽  
Niu Yi Sun ◽  
Guo Hua Wang ◽  
Min Zhang ◽  
Wei Min Shi ◽  
...  

TiCoSb-based half-Heusler compounds, which are narrow band gap semiconductors with a high Seebeck coefficient, have been intensively studied in bulk form but rarely in thin films. In this article TiFexCo1-xSb (x=0, 0.17) thin films were synthesized on n-type single crystal Si (100) and MgO (100) substrates by DC magnetron sputtering followed by rapid thermal annealing. The X-ray diffraction patterns show that Fe doping does not affect the crystallization temperature of TiCoSb phase, but seem to induce the formation of binary phases like TiSb. Hall measurements reveal that the undoped TiCoSb thin films are n-type semiconducting, while TiFe0.2Co0.8Sb turns to p-type with half-order higher carrier concentration of 1.5×1021cm-3. The vibrating sample magnetometer spectrum indicate that the TiCoSb thin film is non-magnetic and TiFexCo1-xSb (x=0.17) is weak magnetic.


1995 ◽  
Vol 410 ◽  
Author(s):  
L. E. Depero ◽  
L. Sangaletti ◽  
C. Schaffnit ◽  
F. Rossi ◽  
P. N. Gibson

ABSTRACTBased on X-ray diffraction and infrared spectroscopy measurements, BN thin films grown by PECVD on silicon substrates have been studied with the aim of identifying the thin film phase. In a set of samples, while the infrared spectra showed characteristic bands of the hexagonal phase, X - ray diffraction patterns only displayed reflections belonging to the cubic BN phase. Therefore, structural models have been developed to explain the apparent inconsistency between the two sets of experimental data. In particular, static disorder effects - which have been introduced in the model starting from the sp2 hybridization of the ordered hexagonal phase, as suggested by the infra-red spectroscopy results - allowed a consistent interpretation of the X-ray diffraction patterns. For another set of samples, which also showed a characteristic hexagonal signal in the IR data, the XRD pattern could not be indexed with any of the BN phases. In this case, the presence of molecular and ionic phases, associated with impurities, was considered in structural modeling studies.


2015 ◽  
Vol 1096 ◽  
pp. 76-79
Author(s):  
Yu Huan Sun ◽  
Juan Qin ◽  
Guo Hua Wang ◽  
Wei Min Shi

Zn-Sb based composite thin films have been prepared by radio frequency magnetron sputtering using a Zn4Sb3 compound target followed by thermal annealing. Sample structure and surface morphology were analyzed by X-ray diffraction (XRD) and atomic force microscopy (AFM). The electrical properties of the films were studied by Hall measurements. The X-ray diffraction patterns reveal that the intensity of diffraction peak of ZnSb phase is enhanced as temperature increasing. Results of AFM shows the rms roughness is getting big with increasing temperature due to the growing crystal grains. Hall measurements indicate that the Zn-Sb composite thin films annealed at different temperatures are p-type conducting with carrier concentrations being on the order of 1019 cm-3.


2011 ◽  
Vol 44 (5) ◽  
pp. 983-990 ◽  
Author(s):  
Chris Elschner ◽  
Alexandr A. Levin ◽  
Lutz Wilde ◽  
Jörg Grenzer ◽  
Christian Schroer ◽  
...  

The electrical and optical properties of molecular thin films are widely used, for instance in organic electronics, and depend strongly on the molecular arrangement of the organic layers. It is shown here how atomic structural information can be obtained from molecular films without further knowledge of the single-crystal structure. C60 fullerene was chosen as a representative test material. A 250 nm C60 film was investigated by grazing-incidence X-ray diffraction and the data compared with a Bragg–Brentano X-ray diffraction measurement of the corresponding C60 powder. The diffraction patterns of both powder and film were used to calculate the pair distribution function (PDF), which allowed an investigation of the short-range order of the structures. With the help of the PDF, a structure model for the C60 molecular arrangement was determined for both C60 powder and thin film. The results agree very well with a classical whole-pattern fitting approach for the C60 diffraction patterns.


1988 ◽  
Vol 66 (5) ◽  
pp. 373-375 ◽  
Author(s):  
C. J. Arsenault ◽  
D. E. Brodie

Zn-rich and P-rich amorphous Zn3P2 thin films were prepared by co-evaporation of the excess element during the normal Zn3P2 deposition. X-ray diffraction techniques were used to investigate the structural properties and the crystallization process. Agglomeration of the excess element within the as-made amorphous Zn3P2 thin film accounted for the structural properties observed after annealing the sample. Electrical measurements showed that excess Zn reduces the conductivity activation energy and increases the conductivity, while excess P up to 15 at.% does not alter the electrical properties significantly.


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.


2019 ◽  
Vol 397 ◽  
pp. 118-124
Author(s):  
Linda Aissani ◽  
Khaoula Rahmouni ◽  
Laala Guelani ◽  
Mourad Zaabat ◽  
Akram Alhussein

From the hard and anti-corrosions coatings, we found the chromium carbides, these components were discovered by large studies; like thin films since years ago. They were pointed a good quality for the protection of steel, because of their thermal and mechanical properties for this reason, it was used in many fields for protection. Plus: their hardness and their important function in mechanical coatings. The aim of this work joins a study of the effect of the thermal treatment on mechanical and structural properties of the Cr/steel system. Thin films were deposited by cathodic magnetron sputtering on the steel substrates of 100C6, contain 1% wt of carbon. Samples were annealing in vacuum temperature interval between 700 to 1000 °C since 45 min, it forms the chromium carbides. Then pieces are characterising by X-ray diffraction, X-ray microanalysis and scanning electron microscopy. Mechanical properties are analysing by Vickers test. The X-ray diffraction analyse point the formation of the Cr7C3, Cr23C6 carbides at 900°C; they transformed to ternary carbides in a highest temperature, but the Cr3C2 doesn’t appear. The X-ray microanalysis shows the diffusion mechanism between the chromium film and the steel sample; from the variation of: Cr, Fe, C, O elements concentration with the change of annealing temperature. The variation of annealing temperature shows a clean improvement in mechanical and structural properties, like the adhesion and the micro-hardness.


1997 ◽  
Vol 12 (3) ◽  
pp. 651-656 ◽  
Author(s):  
P. K. Nair ◽  
L. Huang ◽  
M. T. S. Nair ◽  
Hailin Hu ◽  
E. A. Meyers ◽  
...  

Formation of the ternary compound Cu3BiS3 during annealing of chemically deposited CuS (∼0.3 μm) films on Bi2S3 film (∼0.1 μm on glass substrate) is reported. The interfacial atomic diffusion leading to the formation of the compound during the annealing is indicated in x-ray photoelectron depth profile spectra of the films. The formation of Cu3BiS3 (Wittichenite, JCPDS 9-488) is confirmed by the x-ray diffraction (XRD) patterns. The films are optically absorbing in the entire visible region (absorption coefficient 4 × 104 cm−1 at 2.48 eV or 0.50 μm) and are p-type with electrical conductivity of 102−103 Ω−1 cm−1. Potential applications of these films as optical coatings in the control of solar energy transmittance through glazings and as a p-type absorber film in solar cell structures are indicated.


2009 ◽  
Vol 68 ◽  
pp. 69-76 ◽  
Author(s):  
S. Thanikaikarasan ◽  
T. Mahalingam ◽  
K. Sundaram ◽  
Tae Kyu Kim ◽  
Yong Deak Kim ◽  
...  

Cadmium iron selenide (Cd-Fe-Se) thin films were deposited onto tin oxide (SnO2) coated conducting glass substrates from an aqueous electrolytic bath containing CdSO4, FeSO4 and SeO2 by potentiostatic electrodeposition. The deposition potentials of Cadmium (Cd), Iron (Fe), Selenium (Se) and Cadmium-Iron-Selenide (Cd-Fe-Se) were determined from linear cathodic polarization curves. The deposited films were characterized by x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis by x-rays (EDX) and optical absorption techniques, respectively. X-ray diffraction patterns shows that the deposited films are found to be hexagonal structure with preferential orientation along (100) plane. The effect of FeSO4 concentration on structural, morphological, compositional and optical properties of the films are studied and discussed in detail.


2004 ◽  
Vol 97-98 ◽  
pp. 153-158 ◽  
Author(s):  
Darius Milčius ◽  
L.L. Pranevičius ◽  
V. Širvinskaitė ◽  
T. Šalkus ◽  
A. Kežionis ◽  
...  

Thin films of ZrO2-8mol%Y2O3 have been deposed by pulsed DC magnetron sputtering method. The substrates of Ni-cermet and alloy-600 for the films were used. The results of the investigation of the X-ray diffraction patterns and SEM showed that the films are nanocrystalline and belong to cubic symmetry. The relaxation process is related to the ion transport in thin films. The results of the investigation of the temperature dependencies of thin films ionic conductivity (σ) showed that the dependence σ(T) is caused by the temperature dependence of oxygen vacancy mobility, while the number of charge carriers remains constant with temperature.


Sign in / Sign up

Export Citation Format

Share Document