No-Phonon and Phonon-Assisted Indirect Transitions in Si1−xGex Single Crystals

1996 ◽  
Vol 450 ◽  
Author(s):  
A. Gerhardt
Keyword(s):  
Single Crystals ◽  
Absorption Edge ◽  
Energy Gap ◽  
Differential Method ◽  
Composition Analysis ◽  
Calibration Function ◽  
Absorption Properties ◽  
Transmission Measurements ◽  
Threshold Energies ◽  
Phonon Transition

ABSTRACTThe absorption properties of high quality bulk Si1−xGex single crystals (0 ≤ × ≤ 0.16) are studied. Transmission measurements were performed at the indirect absorption edge. The shape of the absorption edge is characterized by structures attributed to the onset of no-phonon and phonon-assisted indirect optical transitions. Threshold energies have been determined using a differential method. A corrected calibration function for the dependence of the excitonic energy gap on composition is presented for the compositions, where x ranges from 0 to 0.16. The presented calibration function can be used for the composition analysis by an optical method. The analysis is independent of absolute transmission values.A simulation of the absorption spectra by calculations based on second order perturbation theory was used to fit the experimental data This procedure allows to estimate the oscillator strength of the no-phonon transition in dependence on x.

Study on the Near-infrared Absorption Properties of ZnGeP2 Single Crystals

2010 ◽  
Vol 25 (10) ◽  
pp. 1029-1033
Author(s):  
Shi-Xing XIA ◽  
Chun-Hui YANG ◽  
Chong-Qiang ZHU ◽  
Tian-Hui MA ◽  
Meng WANG ◽  
...  
Keyword(s):  
Single Crystals ◽  
Infrared Absorption ◽  
Near Infrared ◽  
Absorption Properties

Temperature shift of the absorption edge in mixed single crystals ofZnxCd1−xSe

1987 ◽  
Vol 36 (2) ◽  
pp. 1174-1177 ◽  
Author(s):  
L. Samuel ◽  
Y. Brada ◽  
A. Burger ◽  
M. Roth
Keyword(s):  
Single Crystals ◽  
Absorption Edge ◽  
Temperature Shift

scholarly journals Estimation of optical parameters of silicon single crystals with different orientations

2019 ◽  
Vol 37 (1) ◽  
pp. 65-70
Author(s):  
M.M. El-Nahass ◽  
H.A.M. Ali
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Single Crystals ◽  
Energy Gap ◽  
Optical Parameters ◽  
Dispersion Energy ◽  
High Frequency Dielectric Constant ◽  
Single Oscillator Model ◽  
Indirect Allowed Transition ◽  
Single Oscillator

AbstractOptical properties of Si single crystals with different orientations (1 0 0) and (1 1 1) were investigated using spectrophotometric measurements in a spectral range of 200 nm to 2500 nm. The data of optical absorption revealed an indirect allowed transition with energy gap of 1.1 ± 0.025 eV. An anomalous dispersion in refractive index. The normal dispersion of the refractive index was discussed according to Wemple-DiDomenico single oscillator model. The oscillator energy Eo, dispersion energy Ed, high frequency dielectric constant ∈∞, lattice dielectric constant ∈L and electronic polarizability αe were estimated. The real ∈1 and imaginary ∈2 parts of dielectric constant were also determined.

Fundamental Optical Absorption Edge in MnGa2Te4 Single Crystals

1988 ◽  
pp. 631-644
Author(s):  
G. A. Medvedkin ◽  
Yu. V. Rud ◽  
M. A. Taibov
Keyword(s):  
Optical Absorption ◽  
Single Crystals ◽  
Absorption Edge ◽  
Optical Absorption Edge

Neutron transmission measurements of zinc and lead single crystals

1988 ◽  
Vol 23 (12) ◽  
pp. 4231-4236 ◽  
Author(s):  
M. Adib ◽  
A. Abdel-Kawy ◽  
Y. Abbas ◽  
A. Ashry ◽  
M. Wahba
Keyword(s):  
Single Crystals ◽  
Neutron Transmission ◽  
Transmission Measurements

Diffuse Reflectance and Transmission Measurements on LiF:Mg,Cu,P Powders and Single Crystals

1993 ◽  
Vol 47 (1-4) ◽  
pp. 123-127 ◽  
Author(s):  
J. McKeever ◽  
D. Macintyre ◽  
S.R. Taylor ◽  
S.W.S. McKeever ◽  
A. Horowitz ◽  
...  
Keyword(s):  
Single Crystals ◽  
Diffuse Reflectance ◽  
Transmission Measurements

Temperature modulated spectroscopy of piezoelectric Bi12TiO20 single crystals near the absorption edge

1982 ◽  
Vol 43 (1) ◽  
pp. 87-89
Author(s):  
M. Grandolfo ◽  
F. Somma ◽  
P. Vecchia ◽  
M. Efendiev ◽  
V. E. Bagiev
Keyword(s):  
Single Crystals ◽  
Absorption Edge

Preparation and Characterisation of (ZnTe)x(CdSe)1−x Single Crystals

1989 ◽  
Vol 161 ◽  
Author(s):  
V.K. Madhu Smitha Rani ◽  
R.P. Vijayalakshmi ◽  
D. Raja Reddy ◽  
B.K. Reddy
Keyword(s):  
Chemical Analysis ◽  
Single Crystals ◽  
Entire Range ◽  
Energy Gap ◽  
Spectral Response ◽  
Alloy System ◽  
Crystalline Form ◽  
Reflection Spectra ◽  
Alloy Material ◽  
P Type

ABSTRACTThe titlematerial is one of the least studied among the II-VI alloy systems. So far it has not been possible to prepare ZnTe in n-type and CdSe in p-type with appreciable conductivities. Moreover ZnTe crystallises in zincblende whereas CdSe crystallises in wurtzite structure. Because of the varied nature of the end compounds, an attempt has been made to prepare single crystals of (ZnTe)x(CdSe)1−x in the entire range of ‘x’. The alloy material in the entire range Xof composition in the single crystalline form was grown by a modified Piper-Plich method. The grown crystals of this alloy system have been subjected to chemical analysis. DTA and DTG studies carried out on these alloys did not show any phasec transitions. However two exothermic peaks associated with increase in mass were noticed. This has been attributed to oxidation effects of Se/Te or Cd/Zn. XRD data though showed some regularity near end compositions there is still some ambiguity for the middle compositions. Energy gap obtained from reflection spectra and also photocurrent spectral response showed bowing. However, there is a marked different feature at one of the end regions. The growth and the results of all the above mentioned investigations are presented and discussed in this paper.

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