scholarly journals A Short Theoretical Note on Optical Absorption of Amorphous Gallium Arsenide in the Infrared Range

1998 ◽  
Vol 20 (3) ◽  
pp. 139-142 ◽  
Author(s):  
M. A. Grado-Caffaro ◽  
M. Grado-Caffaro
Keyword(s):  
Gallium Arsenide ◽  
Optical Absorption ◽  
Absorption Coefficient ◽  
Far Infrared ◽  
Optical Absorption Coefficient ◽  
Infrared Range ◽  
Structural Disorders ◽  
Theoretical Results

An approach to determine the optical absorption coefficient of amorphous GaAs in the far infrared range is developed. Results from this approach are compared with experiment and with other theoretical results. In our formulation, contributions corresponding to both dynamical and structural disorders are taken into consideration.

A SPECIAL MODEL ON OPTICAL ABSORPTION OF AMORPHOUS GaAs IN THE FAR-INFRARED RANGE

1999 ◽  
Vol 13 (17) ◽  
pp. 611-615 ◽  
Author(s):  
M. A. GRADO-CAFFARO ◽  
M. GRADO-CAFFARO
Keyword(s):  
Experimental Data ◽  
Optical Absorption ◽  
Absorption Coefficient ◽  
Far Infrared ◽  
Structural Disorder ◽  
Optical Absorption Coefficient ◽  
Infrared Range ◽  
Electronic Density ◽  
Special Model ◽  
Theoretical Results

The optical absorption coefficient of amorphous GaAs for the far-infrared range is calculated. Results from this calculation are compared with experimental data and with other theoretical results. In our approach, spectrum contribution corresponding to structural disorder is neglected. Moreover, total electronic density of states is determined.

A MODEL FOR OPTICAL ABSORPTION OF AMORPHOUS GaAs IN THE FAR-INFRARED RANGE BY USING AN OPERATIONAL TECHNIQUE

1999 ◽  
Vol 13 (25) ◽  
pp. 919-923 ◽  
Author(s):  
M. A. GRADO-CAFFARO ◽  
M. GRADO-CAFFARO
Keyword(s):  
Optical Absorption ◽  
Absorption Coefficient ◽  
Far Infrared ◽  
Structural Disorder ◽  
Optical Absorption Coefficient ◽  
Infrared Range ◽  
Phonon Density ◽  
Phonon Density Of States ◽  
Operational Technique ◽  
Dynamical Disorder

By considering a sample of amorphous GaAs with a small zone of dynamical disorder, an expression for the optical absorption coefficient and phonon density of states in the low region of the far-infrared range is obtained. To get to this end, absorption corresponding to structural disorder is neglected.

MAXIMUM DYNAMICAL DISORDER IN AMORPHOUS GaAs

1994 ◽  
Vol 08 (03) ◽  
pp. 169-172 ◽  
Author(s):  
M.A. GRADO CAFFARO ◽  
M. GRADO CAFFARO
Keyword(s):  
Optical Absorption ◽  
Absorption Coefficient ◽  
Density Of States ◽  
Far Infrared ◽  
Conduction Band Edge ◽  
Infrared Range ◽  
Phonon Density ◽  
Phonon Density Of States ◽  
Low Frequencies ◽  
Dynamical Disorder

Maximum dynamical disorder in amorphous gallium arsenide is investigated in a special way. In particular, this maximum disorder refers to distance and it is investigated in the context of optical absorption at very low frequencies in the far-infrared range when the photon energy is larger than 2Ec, Ec being the energy at the conduction band edge. Absorption coefficient is calculated and compared with experimental work. Phonon density of states is also evaluated.

scholarly journals First-Order Optical Phonon Processes in Amorphous Clusters

1994 ◽  
Vol 16 (2) ◽  
pp. 109-112 ◽  
Author(s):  
M. A. Grado Caffaro ◽  
M. Grado Caffaro
Keyword(s):  
Optical Absorption ◽  
Optical Phonon ◽  
Far Infrared ◽  
Infrared Range ◽  
First Order ◽  
Structural Disorders ◽  
Amorphous Sic ◽  
Small Clusters ◽  
Dynamical Disorder

Optical absorption in the far infrared range for amorphous GaAs, SiC and Ge is investigated. Small clusters in the context of dynamical disorder are considered. Average values of the absorption contributions due to both dynamical and structural disorders are introduced. In particular, an equation for the spectrum due to dynamical disorder in amorphous SiC is presented.

scholarly journals Optical Absorption Coefficient of a Dispersion of Clusters Composed of a Large Number of Spheres

1987 ◽  
Vol 6 (2) ◽  
pp. 173-181 ◽  
Author(s):  
F. Borghese ◽  
P. Denti ◽  
R. Saija ◽  
G. Toscano ◽  
O. I. Sindoni
Keyword(s):  
Optical Absorption ◽  
Absorption Coefficient ◽  
Optical Absorption Coefficient

Quantitative photopyroelectric out-of-phase spectroscopy of amorphous silicon thin films deposited on crystalline silicon

1991 ◽  
Vol 69 (3-4) ◽  
pp. 317-323 ◽  
Author(s):  
Constantinos Christofides ◽  
Andreas Mandelis ◽  
Albert Engel ◽  
Michel Bisson ◽  
Gord Harling
Keyword(s):  
Thin Films ◽  
Optical Absorption ◽  
Absorption Coefficient ◽  
Dynamic Range ◽  
Crystalline Silicon ◽  
Optical Absorption Coefficient ◽  
Si Substrates ◽  
Silicon Thin Films ◽  
Background Compensation

A photopyroelectric spectrometer with real-time and(or) self-normalization capability was used for both conventional transmission and thermal-wave spectroscopic measurements of amorphous Si thin films, deposited on crystalline Si substrates. Optical-absorption-coefficient spectra were obtained from these measurements and the superior dynamic range of the out-of-phase (quadrature) photopyroelectric signal was established as the preferred measurement method, owing to its zero-background compensation capability. An extension of a photopyroelectric theoretical model was established and successfully tested in the determination of the optical absorption coefficient and the thermal diffusivity of the sample under investigation. Instrumental sensitivity limits of βt ≈ 5 × 10−3 were demonstrated.

Reversible Changes in the Electronic and Optical Properties of Micro-Crystalline ln2O 3-x: A Comparison with Amorphous In2O3-x

1996 ◽  
Vol 426 ◽  
Author(s):  
B. Pashmakov ◽  
H. Fritzsche ◽  
B. Claflin
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Absorption Coefficient ◽  
Ultraviolet Light ◽  
Indium Oxide ◽  
Electrical Conductance ◽  
Inert Gas ◽  
Optical Absorption Coefficient ◽  
Electronic And Optical Properties

AbstractThe electrical conductance and optical absorption coefficient of microcrystalline indium oxide (c – In2 O 3-x ) can be changed reversibly by several orders of magnitude by photoreduction and reoxidation. Photoreduction is achieved by exposure to ultraviolet light hv ≥ 3.5eV in vacuum or an inert gas. The effects are similar to those previously observed in amorphous In2 O3-x

Sign in / Sign up

Export Citation Format

Share Document