scholarly journals Relationship between the optical gap and the optical-absorption tail breadth in amorphous GaAs

2004 ◽  
Vol 96 (12) ◽  
pp. 7052-7059 ◽  
Author(s):  
J. H. Dias da Silva ◽  
R. R. Campomanes ◽  
D. M. G. Leite ◽  
Farida Orapunt ◽  
Stephen K. O’Leary
Keyword(s):  
Optical Absorption ◽  
Optical Gap ◽  
Absorption Tail

An Optical Gap Calibration Applied to the Case of Hydrogenated Amorphous Silicon

1999 ◽  
Vol 557 ◽  
Author(s):  
D. E. Sweenor ◽  
S. K. O'Leary ◽  
B. E. Foutz
Keyword(s):  
Optical Absorption ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Amorphous Semiconductor ◽  
Empirical Measures ◽  
Optical Gap ◽  
Hydrogenated Amorphous ◽  
Absorption Tail ◽  
Empirical Means

AbstractThere are many different empirical means whereby the optical gap of an amorphous semiconductor may be defined. We analyze some hydrogenated amorphous silicon data with respect to a number of these empirical measures for the optical gap. By plotting these various gap measures as a function of the breadth of the optical absorption tail, we provide a means of relating these disparate measures of the optical gap. The applicability of this calibration to another set of hydrogenated amorphous silicon data is investigated.

Compositional Dependence of Optical Absorption in Barium Oxychloride Borate Glasses

2017 ◽  
Vol 6 (1) ◽  
pp. 116-120 ◽  
Author(s):  
M. S. Dahiya ◽  
A. Agarwal ◽  
S. Khasa
Keyword(s):  
Optical Absorption ◽  
Behavioral Change ◽  
Structural Changes ◽  
Optical Band Gap ◽  
Compositional Dependence ◽  
Absorption Data ◽  
Optical Band Gaps ◽  
Mott Model ◽  
Urbach’S Energy ◽  
Absorption Tail

The present communication deals with some significant results pertaining to the optical absorption analysis of glasses in the compositional range of xBaCl2·(30–x)·BaO·68B2O3·2V2O5 (x = 0, 5, 7 and 10 mol%) prepared via convenient melt-quench route. The optical absorption data recorded in wavelength range of 200–800 nm is analyzed by means of Davis-Mott model to evaluate optical band gaps corresponding to direct and indirect transitions. The absorption tail is analyzed to obtain Urbach's energy. Behavioral change in optical band gap and Urbach's energy with changing chlorine concentrations is discussed to predict the structural changes governed in the glass matrix.

PHONON-ASSISTED MAGNETO ABSORPTION IN DIRECT-BAND SEMICONDUCTORS

1967 ◽  
Vol 45 (10) ◽  
pp. 3401-3410 ◽  
Author(s):  
I. P. Batra ◽  
R. R. Haering
Keyword(s):  
Optical Absorption ◽  
Energy Gap ◽  
Level Structure ◽  
Interband Absorption ◽  
Optical Transitions ◽  
Optical Phonons ◽  
Energy Gaps ◽  
Direct Energy ◽  
Direct Band ◽  
Absorption Tail

In polar semiconductors with direct energy gaps, optical absorption is observed for photons with energies well below that corresponding to the energy gap. It is now established that the absorption tail (Urbach's law) is due to indirect phonon-assisted optical transitions involving the absorption of one or more optical phonons of energy kθ. In the present paper we have considered the effect of a magnetic field on the optical absorption in that region of the Urbach tail where second-order processes are dominant. In contrast to the normal direct interband absorption coefficient, the absorption reflects the Landau level structure of valence band and conduction band separately. A discussion is given of the conditions under which such an effect should be observable.

Optical absorption of SiH0.16 films near the optical GAP

1980 ◽  
Vol 35-36 ◽  
pp. 463-468 ◽  
Author(s):  
G.D. Cody ◽  
B. Abeles ◽  
C.R. Wronski ◽  
B. Brooks ◽  
W.A. Lanford
Keyword(s):  
Optical Absorption ◽  
Optical Gap

Effect of Hydrogenation on Structural, Optical and Electrical Properties of Amorphous InAsSb Thin Films

2010 ◽  
Vol 160-162 ◽  
pp. 1508-1512
Author(s):  
Yan Ping Yao ◽  
Chun Ling Liu ◽  
Hai Dong Qi ◽  
Xi Chang ◽  
Chun Wu Wang
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Electrical Properties ◽  
Optical Absorption ◽  
Rf Magnetron Sputtering ◽  
Dark Conductivity ◽  
Optical And Electrical Properties ◽  
Optical Absorption Edge ◽  
Hydrogen Addition ◽  
Optical Gap

Amorphous InAsSb films and hydrogenated InAsSb films are deposited on substrates of quartz glass and silicon by rf magnetron sputtering technique in different gas ambient. The effect of H addition on structure, optical properties and electrical properties of a-InAsSb is studied. It is found that the bonded hydrogen content increases with increasing H2 to Ar flow rate radio(R). When R is 0.1, Hydrogen addition shifts the optical absorption edge to higher energy, decreases the dark conductivity and improves the photo-sensitivity. However, hydrogen addition produces the crystallization of the film at R>0.1. Moreover the optical gap, dark conductivity and photo-sensitivity of the films have a reverse change compared with that in R=0. These results demonstrate that hydrogen has obvious passivation effects on rf sputtered amorphous InAsSb thin films only at R=0.1.

Tuning Optoelectronic Properties of 4H-SiC QDs Using -H, -OH and -F Surface Functionalisation

2015 ◽  
Vol 821-823 ◽  
pp. 375-378 ◽  
Author(s):  
Marzaini Rashid ◽  
Amit Kumar Tiwari ◽  
Neal Wood ◽  
Patrick Briddon ◽  
Jonathan P. Goss ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Absorption ◽  
Quantum Confinement ◽  
Density Functional ◽  
Size Dependent ◽  
Optical Gap ◽  
Quantum Confinement Effects ◽  
Similar Cluster ◽  
Homo And Lumo ◽  
Surface Functionalisation

Density functional calculations were performed for the –H, –OH and –F functional groups adsorbed onto the surface of pseudo-spherical 4H-SiC quantum dots with diameters ranging from 10 to 22 Å. We find that for the investigated diameter range, the H-terminated SiC-quantum dots exhibit strong size dependent quantum confinement effects, while for –F and –OH terminations, the optical gap remains largely unchanged. The –H termination shows an optical absorption onset well above that of –F and –OH for a similar cluster size, which is attributed to the localisation of HOMO and LUMO states to the quantum dot core. Based on our calculations, we suggest that the –H functionalisation is a more promising route for engineering the optical properties of SiC-quantum dots, since this could lead to a wider control over the optical absorption onsets, when compared to –OH and –F terminations.

Optical Absorption Tail and Superparamagnetism of γ-Fe2O3

1996 ◽  
Vol 225-227 ◽  
pp. 725-732 ◽  
Author(s):  
J.K. Vassiliou ◽  
V. Mehrotra ◽  
J.W. Otto ◽  
N.R. Dollahon
Keyword(s):  
Optical Absorption ◽  
Absorption Tail

Optical absorption above the optical gap of amorphous silicon hydride

1982 ◽  
Vol 8 (1-3) ◽  
pp. 231-240 ◽  
Author(s):  
G.D. Cody ◽  
B.G. Brooks ◽  
B. Abeles
Keyword(s):  
Optical Absorption ◽  
Amorphous Silicon ◽  
Silicon Hydride ◽  
Optical Gap

Optical Absorption Peculiarities of Al-Si-N Coatings Produced by Magnetron Sputtering

2016 ◽  
Vol 712 ◽  
pp. 3-8 ◽  
Author(s):  
Alexandr V. Kabyshev ◽  
Fedor V. Konusov ◽  
Alexander L. Lauk ◽  
Alexey M. Lebedinskiy ◽  
Victor N. Legostaev ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Magnetron Sputtering ◽  
Mechanical Characteristics ◽  
Nitrogen Pressure ◽  
Localized States ◽  
Optical Parameters ◽  
Semiclassical Analysis ◽  
Average Value ◽  
Optical Gap ◽  
Maximal Average

In this paper the optical absorption characteristics of Al–Si–N coatings, deposited by magnetron sputtering on the substrates from silicon single crystals and glass were studied. The influence of conditions deposition on optical properties has been determined. The characteristics of interband and exponential absorption are determined by influence of localized states (LS) of defects continuously distributed in the band gap (BG) and reflect the influence on properties of crystalline and amorphous components material of coatings. The interband absorption is realized via the allowed indirect transitions through the optical gap 2.7–2.8 eV and direct transitions through the gap 3.8–3.96 eV. The interrelations between the parameters of interband and exponential absorption are typical for the naterials, whose properties are determined by a static and/or dynamic disordering of the crystal lattice by the defects of a different nature. Maximal average value of the BG width is 4.8–5.1 eV in the scope of semiclassical analysis applied to amorphous and strongly defective materials. The optical parameters of deposited coatings are changed in correlation with a changing of the mechanical characteristics in dependency on the nitrogen pressure.

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