Comparison of Structural, Electrical and Thermoelectric Properties of Vacuum Evaporated SnTe Films of Varied Thickness

2020 ◽  
Vol 20 (6) ◽  
pp. 3879-3887
Author(s):  
Praveen Tanwar ◽  
A. K. Panwar ◽  
Sukhvir Singh ◽  
A. K. Srivastava
Keyword(s):  
Thin Films ◽  
High Resolution ◽  
Surface Morphology ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Electrical Measurements ◽  
Average Roughness ◽  
Thermoelectric Measurements ◽  
Tin Telluride ◽  
Te Material

As a key type of promising thermoelectric (TE) material p-type Tin Telluride (SnTe) vacuum evaporated thin films synthesized at room temperature (RT) on a glass substrate, report a significant enhancement in the figure of merit (ZT) value. The thicknesses of the nanostructured thin films were kept about 145 nm and 275 nm. High-resolution X-ray diffraction (HRXRD) outlines the polycrystalline nature in both thin films. Surface morphology of these films is composed of grains of variable sizes as elucidated by scanning electron microscopy (SEM). This observation is further confirmed by atomic force microscopy (AFM) wherein the average roughness, surface skewness, and surface kurtosis parameters are used to analyze the surface morphology. Local microstructural features and crystalline structure have been confirmed from High-resolution transmission electron microscope (HRTEM) and the selected area electron diffraction (SAED) pattern, respectively. Four probes method was used to determine electrical measurements which confirm that the thin films have semi-metallic nature. Thermoelectric measurements carried out on these films resulted that the figure of merit increases as the thickness of the film increases. The maximum ZT value of ˜1.02 is obtained at room temperature for the thin film of thickness 275 nm.

AFM Study of Surface Morphology of Aluminum Nitride Thin Films

1995 ◽  
Vol 388 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Yoshikazu Nakamura ◽  
Shigekazu Hirayama ◽  
Yuusaku Naota
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Substrate Temperature ◽  
Single Crystal ◽  
Room Temperature ◽  
Ion Beam ◽  
Soda Lime ◽  
Silicon Single Crystal ◽  
Soda Lime Glass ◽  
Average Roughness

AbstractAluminum nitride (AlN) thin films have been synthesized by ion-beam assisted deposition method. Film deposition has been performed on the substrates of silicon single crystal, soda-lime glass and alumin A. the influence of the substrate roughness on the film roughness is studied. the substrate temperature has been kept at room temperature and 473K and the kinetic energy of the incident nitrogen ion beam and the deposition rate have been fixed to 0.5 keV and 0.07 nm/s, respectively. the microstructure of the synthesized films has been examined by X-ray diffraction (XRD) and the surface morphology has been observed by atomic force microscopy(AFM). IN the XRD patterns of films synthesized at both room temperature and 473K, the diffraction line indicating the alN (10*0) can be discerned and the broad peak composed of two lines indicating the a1N (00*2) and a1N (10*1) planes is also observed. aFM observations for 100 nm films reveal that (1) the surface of the films synthesized on the silicon single crystal and soda-lime glass substrates is uniform and smooth on the nanometer scale, (2) the average roughness of the films synthesized on the alumina substrate is similar to that of the substrate, suggesting the evaluation of the average roughness of the film itself is difficult in the case of the rough substrate, and (3) the average roughness increases with increasing the substrate temperature.

Influence of Momentary Annealing on the Nanoscale Surface Morphology of Room Temperature Pulsed Laser Deposited NiO(111) Epitaxial Thin Films on Atomically Stepped Sapphire (0001) Substrates

2013 ◽  
Vol 1507 ◽  
Author(s):  
Ryosuke Yamauchi ◽  
Geng Tan ◽  
Daishi Shiojiri ◽  
Nobuo Tsuchimine ◽  
Koji Koyama ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Film Surface ◽  
Transient State ◽  
Epitaxial Thin Films ◽  
Flat Surfaces ◽  
Surface Nanostructure ◽  
Atomically Flat

ABSTRACTWe examined the influence of momentary annealing on the nanoscale surface morphology of NiO(111) epitaxial thin films deposited on atomically stepped sapphire (0001) substrates at room temperature in O2 at 1.3 × 10−3 and 1.3 × 10−6 Pa using a pulsed laser deposition (PLD) technique. The NiO films have atomically flat surfaces (RMS roughness: approximately 0.1–0.2 nm) reflecting the step-and-terrace structures of the substrates, regardless of the O2 deposition pressure. After rapid thermal annealing (RTA) of the NiO(111) epitaxial film deposited at 1.3 × 10−3 Pa O2, a periodic straight nanogroove array related to the atomic steps of the substrate was formed on the film surface for 60 s. In contrast, the fabrication of a transient state in the nanogroove array formation was achieved with RTA of less than 1 s. However, when the O2 atmosphere during PLD was 1.3 × 10−6 Pa, random crystal growth was observed and resulted in a disordered rough surface nanostructure after RTA.

Characteristics of CZTSSe Thin Films Prepared by Selenization of Sputtered Cu, Sn and ZnS Layers

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940040 ◽  
Author(s):  
N. Akcay ◽  
S. Ozcelik ◽  
E. Zaretskaya ◽  
R. Juskenas
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Surface Morphology ◽  
Magnetron Sputtering ◽  
Room Temperature ◽  
Sem Study ◽  
Packed Structure

We reported the growth of CZTSSe thin films on Mo-coated SLG substrates by the two-step approach which includes the deposition of precursor films by the magnetron sputtering method at room temperature followed by selenization of the precursor films at 560∘C. Formation of CZTSSe films with the kesterite structure was confirmed by XRD and Raman spectroscopy analyses. The films are slightly Cu-rich and Zn-deficient. SEM study shown that the films have uniform surface morphology and densely packed structure without any voids and cracks.

The effect of stoichiometry on the microstructure and properties of lead lanthanum titanate thin films

1995 ◽  
Vol 10 (11) ◽  
pp. 2777-2787 ◽  
Author(s):  
Ashraf R. Khan ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Relative Permittivity ◽  
Room Temperature ◽  
Optical Transmittance ◽  
High Resistivity ◽  
Charge Storage ◽  
Electrical Measurements ◽  
Storage Density ◽  
Lanthanum Titanate

Thin films of Lead Lanthanum Titanate (PLT) corresponding to 28 at. % of La were prepared by the metal-organic decomposition (MOD) process. The films were fabricated from two solutions of different composition. The composition of the first solution was determined, assuming that the incorporation of La3+ in the PbTiO3 structure gives rise to A-site or Pb vacancies, whereas for the composition of the other solution the creation of B-site or Ti vacancies was assumed. The effect of excess lead on the microstructure and the optical and electrical properties was studied for 0% to 20% excess PbO. The x-ray diffraction patterns of all films at room temperature indicated a cubic structure with a lattice constant of 3.92 Å. Optical and electrical measurements showed the films made assuming B-site vacancies had better properties. In general, excess PbO was found to improve the optical transmittance as well as the electrical properties of films. However, in films assuming the formation of B-site vacancies, PLT showed improved electrical properties only up to 5–10% excess PbO, while higher PbO additions had a deleterious effect. The films had a high resistivity, good relative permittivity, low loss, very low leakage current density, and high charge storage density. A type-B film with 10% excess Pb had a relative permittivity of 1340 at 100 kHz and a charge storage density of around 16.1 μC/cm2 at a field of 200 kV/cm at room temperature.

p-Type Field Effect Transistor and UV-Photoconductive Characteristics of Na Doped ZnMgO Thin Films

2013 ◽  
Vol 668 ◽  
pp. 681-685
Author(s):  
Ya Xue ◽  
Hai Ping He ◽  
Zhi Zhen Ye
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Carrier Mobility ◽  
Room Temperature ◽  
Zno Films ◽  
Electrical Measurements ◽  
Acceptor Dopant ◽  
Znmgo Thin Film ◽  
Effect Transistor ◽  
P Type

In this study, the authors have presented results for fabricated ZnO based FET and the UV-photoconductive characteristics of Na doped ZnMgO thin films. The electrical measurements confirmed that the conductivity of the Na doped ZnMgO thin film is p-type, and the carrier mobility was estimated to be 2.3 cm2V-1S-1. Moreover, after exposed to the 365 nm ultraviolet light, the Na doped ZnMgO thin films still exhibited p-type behavior under gate voltage ranging from -5 to 2 V, and the Id increased a little while the carrier mobility did not change much. The photocurrent was measured under a bias of 6 V in air at room temperature. The films performed a higher current intensity after the illumination. The instantaneous rise of the photocurrent was completed when exposed to the 365 nm ultraviolet for 20 s, after switching the ultraviolet off the photocurrent decayed in a slower rate. The enhance rate of photocurrent was about 1.33 %. Conclusively, Na is a considerable acceptor dopant for making high quality p-type ZnO films, and the tiny change in the photocurrent of p-type Na doped ZnMgO thin film made it relatively stable when fabricating LEDs and other optoelectronic devices.

scholarly journals Piezoresponse force microscopy and dielectric spectroscopy study of Ba0.6Sr0.4TiO3 thin films

2019 ◽  
Vol 09 (03) ◽  
pp. 1950025
Author(s):  
Dionizy Czekaj ◽  
Agata Lisińska-Czekaj
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Room Temperature ◽  
Sol Gel ◽  
Film Surface ◽  
Piezoresponse Force Microscopy ◽  
Elementary Cell ◽  
Structure Property ◽  
Average Roughness ◽  
Force Microscopy

Research on synthesis, characterization and determination of processing — structure — property relationships of commercially important ferroelectric thin films has been performed. The sol–gel type solution deposition technique was applied to produce good quality thin films of [Formula: see text][Formula: see text]TiO3 (BST60/40) chemical composition on the stainless steel substrates. The thin films were characterized in terms of their microstructure, crystal structure, phase composition, piezoelectric and dielectric properties. It was found that the BST60/40 thin film adopted the cubic structure at room temperature with an elementary cell parameter [Formula: see text] Å. Morphology of the thin film surface was studied with Atomic Force Microscopy (AFM). Average roughness of the thin films surface was found ([Formula: see text]m). Piezoresponse Force Microscopy (PFM) was applied for the thin film characterization. Active piezoelectric regions were found in BST60/40 thin film. Therefore, dielectric response measured at room temperature was studied in assumption of piezoelectric electric equivalent circuit.

Microstructure and Surface Structure Evolution in AlCu Polycrystalline Thin Films

1999 ◽  
Vol 562 ◽  
Author(s):  
Adriana E. Lita ◽  
John E. Sanchez
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Fiber Orientation ◽  
Film Formation ◽  
Deposition Process ◽  
Structure Evolution ◽  
Average Roughness ◽  
Deposition Rates ◽  
Cu Films ◽  
Polycrystalline Thin Films

ABSTRACTThe evolution of crystallographic texture, grain size and surface morphology in magnetron sputter deposited Al-0.5wt.% Cu polycrystalline thin films is reported as a function of film thickness for SiO2 and SiO2/Ti underlayers for several deposition rates. Regardless of the underlayer type, the initial ≈ 10 nm of the Al-Cu films is nearly randomly oriented, with the films developing a (111) out-of-plane texture which increases in strength with thickness during deposition. The AlCu films on sputtered Ti underlayers developed an exact (111) fiber orientation while Al-Cu films on oxide substrates were offset ≈ 5° from exact fiber orientation. Higher deposition rates were found to result in slightly better (111) textured 20 nm AlCu films. The surface morphology of films, determined by Atomic Force Microscopy (AFM), revealed two regimes of average roughness (Rrms) evolution during deposition. Rrms decreased early in the deposition process, followed by a roughening regime where Rrms increased with thickness. These results are discussed in terms of mechanisms such as grain growth, which help to determine microstructure development during film formation from the vapor.

scholarly journals Growth and Characterization of M-Plane GaN Thin Films Grown on γ-LiAlO2 (100) Substrates

Scanning ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Yu-Chiao Lin ◽  
Ikai Lo ◽  
Hui-Chun Shih ◽  
Mitch M. C. Chou ◽  
D. M. Schaadt
Keyword(s):  
Thin Films ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Surface Morphology ◽  
Molecular Beam ◽  
Flux Ratio ◽  
Anisotropic Growth ◽  
X Ray Diffraction ◽  
X Ray

M-plane GaN thin films were grown on LiAlO2 substrates under different N/Ga flux ratios by plasma-assisted molecular beam epitaxy. An anisotropic growth of M-plane GaN was demonstrated against the N/Ga flux ratio. As the N/Ga flux ratio decreased by increasing Ga flux, the GaN surface trended to a flat morphology with stripes along [112-0]. According to high-resolution X-ray diffraction analysis, Li5GaO4 was observed on the interface between GaN and LiAlO2 substrate. The formation of Li5GaO4 would influence the surface morphology and crystal quality.

Pseudo-Superlattices of Bi2Te3 Topological Insulator Films with Enhanced Thermoelectric Performance

2011 ◽  
Vol 1344 ◽  
Author(s):  
V. Goyal ◽  
D Teweldebrhan ◽  
A.A. Balandin
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Topological Insulator ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Laser Flash ◽  
Thermoelectric Efficiency ◽  
Thermoelectric Figure ◽  
Surface Transport ◽  
Film Thinning

ABSTRACTIt was recently suggested theoretically that atomically thin films of Bi2Te3 topological insulators have strongly enhanced thermoelectric figure of merit. We used the “graphene-like” exfoliation process to obtain Bi2Te3 thin films. The films were stacked and subjected to thermal treatment to fabricate pseudo-superlattices of single crystal Bi2Te3 films. Thermal conductivity of these structures was measured by the “hot disk” and “laser flash” techniques. The room temperature in-plane and cross-plane thermal conductivity of the stacks decreased by a factor of ∼2.4 and 3.5 respectively as compared to that of bulk. The strong decrease of thermal conductivity with preserved electrical properties translates to ∼140-250% increase in the thermoelectric figure if merit. It is expected that the film thinning to few-quintuples, and tuning of the Fermi level can lead to the topological insulator surface transport regime with the theoretically predicted extraordinary thermoelectric efficiency.

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