Zinc sulfide (ZnS) energy gap, cubic modification

2005 ◽  
pp. 1-4
Author(s):  
Keyword(s):  
Zinc Sulfide ◽  
Energy Gap

Zinc Sulfide Nanoscaled Buffer Layers for Cu(In,Ga)Se2 Thin Film Solar Cells by Chemical Bath Deposition

2008 ◽  
Vol 51 ◽  
pp. 125-130 ◽  
Author(s):  
Rong Fuh Louh ◽  
Warren Wu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Solar Cells ◽  
Zinc Sulfide ◽  
Chemical Bath Deposition ◽  
Energy Gap ◽  
Buffer Layers ◽  
Thin Film Solar Cells ◽  
Complexing Agents ◽  
Study Results

Chemical bath deposition (CBD) is a fairly simple synthetic route to prepare II-VI semicondutive zinc sulfide thin films, which can be prepared on the flat surface of glass or silicon wafer substrates in the solution containing the precursors of zinc and sulfur ions in terms of ambient conditions of varying acidity. This study particularly aims at the growth dependence and optical property of ZnS thin films in the CBD process by different experiment parameters, whereas we intend to choose suitable types of zinc ionic precursors to be coupled with various CBD parameters such as reaction temperature and time, precursor concentration, types and complexing agents as well as post-deposition heat treatment conditions. Addition of different concentration of ethylenediamine, ammonium sulfate, sodium citrate and hydrazine in the CBD reaction process was used to control the adequate growth rate of ZnS thin films. As a consequence, the rapid thermal annealing was employed to enhance the film uniformity and thickness evenness, transmittance and the energy gap of ZnS samples. The results would lead to a potential application of buffer layer for the Cu (In,Ga)Se2 based thin film solar cells. The analytic instrument including SEM, AFM, UV-VIS were used to examine the CBD-derived nanosized ZnS buffer layers for the thin film solar cells. The ZnS thin films prepared by the chemical bath deposition in this study results in film thickness of 80 ~ 100 nm, high transmittance of 80~85% and the energy gap of 3.89 ~ 3.98 eV.

scholarly journals Structural and Optoelectronic Properties of Zinc Sulfide Thin Films Synthesized by Co-Precipitation Method

2019 ◽  
Vol 27 (2) ◽  
pp. 287-302
Author(s):  
V.H. Choudapur ◽  
S.B. Kapatkar ◽  
A.B. Raju
Keyword(s):  
Zinc Sulfide ◽  
Energy Gap ◽  
Quantum Confinement Effect ◽  
Wide Bandgap ◽  
Precipitation Method ◽  
Cubic Phase ◽  
Uv Detectors ◽  
Sulphur Concentration ◽  
Co Precipitation ◽  
Sulfide Nanocrystals

Abstract Wide bandgap Zinc Sulfide nanocrystals are prepared by a simple co-precipitation method at different precursor concentrations. The influence of sulphur concentration in Zinc sulfide on morphological, optical and electric properties is found to be significant. The Zinc Sulfide nanomaterial was prepared using low-cost starting materials and deionised water as the solvent. As synthesized Zinc Sulfide nanocrystals were analyzed using X-ray diffraction (XRD), Energy Dispersive Spectroscopy (EDS) analysis, UV-Visible Spectrophotometry, Photoluminescence (PL), Scanning electron Microscopy (SEM), Ellipsometry techniques and electric conductivity measurements. XRD patterns revealed that ZnS nanocrystals are polycrystalline, cubic phase with (111) preferred orientation. The obtained crystallites have sizes in the range of 5 to 11 nm. EDS pattern confirms the purity of the films. From optical absorption measurements, it is clear that the direct energy gap decreases from 5.2 to 4.4eV with the increase in sulphur concentration in ZnS and exhibit large quantum confinement effect. Ellipsometry was used to determine the optical constants and film thickness. The films deposited on ITO – coated glass was used to record the IV Characteristics of the films by two probe method. The wide-bandgap, conducting materials have applications in optoelectronic devices such as high-frequency UV detectors and thin-film solar cells.

Formation of high temperature phase in flash-evaporated SnSe films

1990 ◽  
Vol 48 (4) ◽  
pp. 698-699
Author(s):  
J.P.S. Hanjra
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Energy Gap ◽  
Dominant Role ◽  
Fine Powder ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Water Mixture ◽  
Flash Evaporation ◽  
Photovoltaic Applications

Tin mono selenide (SnSe) with an energy gap of about 1 eV is a potential material for photovoltaic applications. Various authors have studied the structure, electronic and photoelectronic properties of thin films of SnSe grown by various deposition techniques. However, for practical photovoltaic junctions the electrical properties of SnSe films need improvement. We have carried out investigations into the properties of flash evaporated SnSe films. In this paper we report our results on the structure, which plays a dominant role on the electrical properties of thin films by TEM, SEM, and electron diffraction (ED).Thin films of SnSe were deposited by flash evaporation of SnSe fine powder prepared from high purity Sn and Se, onto glass, mica and KCl substrates in a vacuum of 2Ø micro Torr. A 15% HF + 2Ø% HNO3 solution was used to detach SnSe film from the glass and mica substrates whereas the film deposited on KCl substrate was floated over an ethanol water mixture by dissolution of KCl. The floating films were picked up on the grids for their EM analysis.

Effect of the structural changes on the mechanical properties of the sintered films

2016 ◽  
Vol 12 (1) ◽  
pp. 4141-4144
Author(s):  
Garima Jain
Keyword(s):  
Crystallite Size ◽  
Lattice Constant ◽  
Structural Changes ◽  
Structural Investigation ◽  
Energy Gap ◽  
Lattice Parameter ◽  
Metal Chalcogenides ◽  
Optical Energy Gap ◽  
Tin Telluride ◽  
Physical Quantities

Polycrystalline films of tin telluride were prepared by sintering technique. The structural investigation of the films with different thicknesses enables to determine lattice parameter, crystallite size and strain existing in the films. The XRD traces showed that strain was tensile in nature. The crystallite size increases with thickness while strain decreases. Higher the value of tensile strain, larger is the lattice constant. The optical energy gap shows a descending nature with increasing strain and so with the lattice constant. Such an attempt made to delve into interdependence of basic physical quantities helps to explore the properties of SnTe and utilize it as an alternative to heavy metal chalcogenides in various technological applications.  

Structure, Stability and Water Adsorption on Ultra-Thin TiO2 Supported on TiN

2019 ◽  
Author(s):  
Jose Julio Gutierrez Moreno ◽  
Marco Fronzi ◽  
Pierre Lovera ◽  
alan O'Riordan ◽  
Mike J Ford ◽  
...  
Keyword(s):  
Density Functional ◽  
Water Adsorption ◽  
Chemical Potential ◽  
Energy Gap ◽  
Molecular Water ◽  
Structure Stability ◽  
Ambient Conditions ◽  
Rutile Structure ◽  
The Stability ◽  
The One

<p></p><p>Interfacial metal-oxide systems with ultrathin oxide layers are of high interest for their use in catalysis. In this study, we present a density functional theory (DFT) investigation of the structure of ultrathin rutile layers (one and two TiO<sub>2</sub> layers) supported on TiN and the stability of water on these interfacial structures. The rutile layers are stabilized on the TiN surface through the formation of interfacial Ti–O bonds. Charge transfer from the TiN substrate leads to the formation of reduced Ti<sup>3+</sup> cations in TiO<sub>2.</sub> The structure of the one-layer oxide slab is strongly distorted at the interface, while the thicker TiO<sub>2</sub> layer preserves the rutile structure. The energy cost for the formation of a single O vacancy in the one-layer oxide slab is only 0.5 eV with respect to the ideal interface. For the two-layer oxide slab, the introduction of several vacancies in an already non-stoichiometric system becomes progressively more favourable, which indicates the stability of the highly non-stoichiometric interfaces. Isolated water molecules dissociate when adsorbed at the TiO<sub>2</sub> layers. At higher coverages the preference is for molecular water adsorption. Our ab initio thermodynamics calculations show the fully water covered stoichiometric models as the most stable structure at typical ambient conditions. Interfacial models with multiple vacancies are most stable at low (reducing) oxygen chemical potential values. A water monolayer adsorbs dissociatively on the highly distorted 2-layer TiO<sub>1.75</sub>-TiN interface, where the Ti<sup>3+</sup> states lying above the top of the valence band contribute to a significant reduction of the energy gap compared to the stoichiometric TiO<sub>2</sub>-TiN model. Our results provide a guide for the design of novel interfacial systems containing ultrathin TiO<sub>2</sub> with potential application as photocatalytic water splitting devices.</p><p></p>

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