Structural and Electronic Properties of Polycrystalline Cu(In,Ga)(S,Se)2 Alloys

2001 ◽  
Vol 668 ◽  
Author(s):  
I. M. Kötschau ◽  
M. Turcu ◽  
U. Rau ◽  
H. W. Schock
Keyword(s):  
Optical Properties ◽  
High Vacuum ◽  
Alloy System ◽  
Growth Mode ◽  
Growth Region ◽  
Rich Phase ◽  
Band Position ◽  
Structural And Electronic Properties ◽  
Grade Material ◽  
Energetic Position

ABSTRACTWe present a systematic study on the polycrystalline Cu(In,Ga)(S,Se)2 alloys with a gallium to indium ratio of Ga/(Ga+In)<0.3 and a sulfur to selenium ratio varying in the range between 0<S/(S+Se)<1. All samples were grown by coevaporation of the elements at constant rates under high vacuum conditions. The formation of island-like (Cu,S,Se) segregations correlate with the sulfur to selenium ratio in the layer and are found in the growth region near the copper rich phase boundary. These segregations are related to a preferred incorporation of sulfur in the copper rich growth mode. We obtain solar cell grade material from an indium rich growth mode up to a sulfur to selenium ratio of S/(S+Se)=0.9. A detailed analysis of the electronic and optical properties of Mo/CIGSSe/CdS/ZnO:Al heterojunctions allows us to determine the energetic position of the bands within the Cu(In,Ga)(S,Se)2 alloy system. We find that contrary to the Cu(In,Ga)(Se)2 alloy system the valence band position is significantly lowered with increasing bandgap.

Optical Properties of Nano-Structure Tungsten-Doped Vanadium Oxide

2012 ◽  
Author(s):  
W. B. Cai ◽  
F. Wang ◽  
Y. P. Miao ◽  
J. Wei ◽  
K. L. Zhang
Keyword(s):  
Optical Properties ◽  
Transition Temperature ◽  
Oxide Film ◽  
Vanadium Oxide ◽  
High Vacuum ◽  
Infrared Transmission ◽  
Dc Magnetron Sputtering ◽  
Nano Structure ◽  
Before And After ◽  
Deposited Film

Tungsten-doped vanadium oxide has been proved to decrease the transition temperature, which enables vanadium oxide film to be more promising. Besides, the nano-structure can improve the properties of the film when compared with the as-deposited film. In this letter, a nano-structure tungsten-doped vanadium oxide film is proposed. Tungsten-doped vanadium oxide film was deposited on the Si (400) substrate by DC magnetron sputtering. The doping level was controlled by adjusting the sputtering time. Then the as-deposited film was annealed to form a nano-structure film at the temperature of 500 °C for 1 h in high vacuum. The morphology and crystalline structure of such films were characterized by AFM and XRD, respectively. Optical properties of the films were tested by FTIR, mainly comparing the infrared transmission before and after annealing.

scholarly journals Effect of Doping Concentration on the Optical Properties of Indium-Doped Gallium Arsenide Thin FILMS

2016 ◽  
Vol 40 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Md Saiful Islam ◽  
Chitra Das ◽  
Mehnaz Sharmin ◽  
Kazi Md Amzad Hussain ◽  
Shamima Choudhury
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Doping Concentration ◽  
High Vacuum ◽  
Band Gap Energy ◽  
Crystal Thickness ◽  
Thermal Evaporation Method ◽  
Gap Energy ◽  
Indium Doping

Effects of indium doping (concentration 0.2, 0.3 and 0.4%) on the optical properties of GaAs thin films were studied. Thin films of 600 nm were grown onto chemically and ultrasonically cleaned glass substrate by thermal evaporation method in high vacuum (~10-4 Pa) at 50°C fixed substrate temperature. The samples were annealed for 15 minutes at a fixed temperature of 200°C. The thicknesses of films were being measured in situ by a quartz crystal thickness monitor during deposition. The transmittance and reflectance data were found using UV-VIS-NIR spectrophotometer in the photon wavelength range of 310 ~ 2500 nm. These data were utilized to compute the absorption coefficient, refractive index, extinction co-efficient and band gap energy of the studied films. Here transmittance was found 78 for 0.2% indium doping concentration. The band gap energy decreased with the increase of doping concentration.Journal of Bangladesh Academy of Sciences, Vol. 40, No. 2, 179-186, 2016

Optical properties of non-uniform thickness thin films of the glass-alloy system Cu–As–Se

1997 ◽  
Vol 55 (1) ◽  
pp. 108-113 ◽  
Author(s):  
J M González-Leal ◽  
E Márquez ◽  
J B Ramírez-Malo ◽  
J J Ruiz-Pérez ◽  
R Jiménez-Garay ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Alloy System ◽  
Uniform Thickness ◽  
Glass Alloy

Structural and Optical Properties of the Thermally Stable Amorphous Si1−xBx Alloy.

1993 ◽  
Vol 297 ◽  
Author(s):  
Johan R. A. Carlsson ◽  
X.H. Li ◽  
S.F. Gong ◽  
H.T.G. Hentzell
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Annealing Temperature ◽  
High Vacuum ◽  
Vacuum System ◽  
Structural And Optical Properties ◽  
Microstructural Alterations ◽  
Amorphous Si ◽  
Means Of Transmission ◽  
Quartz Substrates

Thin amorphous Si1−xBx films were co-evaporated onto pre-oxidized (100) Si wafers and quartz substrates, by using a high vacuum system with 2 electron guns. Films were deposited in a composition range from x=0 to x=0.5. In order to study how the structural and optical properties depended on concentration and annealing temperature, heat treatments were carried out at temperatures from 400 up to 1000°C. The films were characterized by means of transmission electron microscopy (TEM), Auger electron spectroscopy (AES), and light absorption spectrophotometry. It is shown that the amorphous Si1−xBx alloy is stable up to 1000°C at certain compositions and that the optical band gap of the alloy increases gradually with increasing annealing temperature up to 700 - 900°C, and then increases rapidly when annealed at a higher temperature by about 0.5 eV. These changes can be associated with microstructural alterations. The relationship between the microstructure and the band gap of the films is discussed.

Growth-mode-induced surface morphology and its relation to optical properties of GaAs single quantum wells

1997 ◽  
Vol 175-176 ◽  
pp. 1167-1172 ◽  
Author(s):  
R. Hey ◽  
I. Gorbunova ◽  
M. Ramsteiner ◽  
M. Wassermeier ◽  
L. Däweritz ◽  
...  
Keyword(s):  
Optical Properties ◽  
Surface Morphology ◽  
Quantum Wells ◽  
Growth Mode ◽  
Single Quantum

Calculations of the Macroscopic Linear and Nonlinear Optical Properties of Nematic Liquid Crystals

1999 ◽  
Vol 597 ◽  
Author(s):  
Steven M. Risser ◽  
Kim F. Ferris ◽  
Gregory J. Exarhos ◽  
J. Corey Morgan
Keyword(s):  
Optical Properties ◽  
Liquid Crystals ◽  
Local Environment ◽  
Geometrical Parameters ◽  
Nematic Order ◽  
Structural And Electronic Properties ◽  
Donor Acceptor ◽  
Small Set ◽  
Complete Set ◽  
Dynamical Fluctuations

AbstractMany studies have focused on the computation of the structural and electronic properties of liquid crystal molecules in a single static conformation. However, a complete and quantitatively accurate description of the macroscopic optical properties of liquid crystals must also include effects due to the long-range nematic order, the anisotropic local environment surrounding the molecules, and the dynamical fluctuations of the molecules. In this paper, we explore methods to simplify computation of the molecular average second hyperpolarizability of the nematogen 4-n-pentyl-4-cyanobiphenyl (5CB). The model we develop relates changes in the geometrical parameters of the molecule to corresponding changes in the hyperpolarizability. The model is first applied to a simple donor-acceptor substituted polyene, and then to 5CB. Use of a small set of geometrical variables results in a slight increase in the RMS deviation of the predicted hyperpolarizability over the deviation obtained from a complete set. We then discuss the importance of this work for the development of means to calculate macroscopic optical properties.

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