Cody disorder: Absorption-edge relationships in hydrogenated amorphous silicon

Ravindra, Nuggehalli M.; Demichelis, Francesca

doi:10.1103/physrevb.32.6591

Cited by 9 publications

(3 citation statements)

References 23 publications

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“…The concept of equivalence of structural and compositional disorder has explained the relationship between the optical bandgap and Urbach energy 39 . An attempt to analyze the model of 39 has been made 40 to better understand the role of topological and thermal disorder in determining the optical bandgap in amorphous solids.…”

Section: Resultsmentioning

confidence: 99%

Disorder and compositional dependences in Urbach-Martienssen tails in amorphous (GeTe)x(Sb2Te3)1−x alloys

Shportko

2019

Sci Rep

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This work focuses on the compositional dependences in parameters that govern the optical properties of (GeTe) x (Sb 2 Te 3 ) 1−x amorphous alloys in the wide spectral range from above the phonons and to the inter-band electronic transitions. We studied the absorption edge fluctuations that are linked to the variations of the bandgap E g , the width of Urbach-Martienssen tails E U , the Tauc parameter B 1/ 2 , and average halfwidth < FWHM > of Raman bands in amorphous (GeTe) x (Sb 2 Te 3 ) 1−x alloys at various temperatures. Obtained results reveal the compositional trends in the influence of the disordering on the absorption processes in studied alloys.

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Section: Resultsmentioning

confidence: 99%

Disorder and compositional dependences in Urbach-Martienssen tails in amorphous (GeTe)x(Sb2Te3)1−x alloys

Shportko

2019

Sci Rep

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“…Thus, we can speculate that an ordered pattern from native defects (DDW) accumulated inside the F2 and F3 samples due to the memory effect isn't able to change their degree of structural (topological) disorder. Usually, additional structural disorder related to the memory effect in crystals with INC -phase may arise due to [76,77]: charge carriers trapping by defects located at positions corresponding to minimum of DDW potential; compositional fluctuation or chemical instability; distortions of the underlying lattice. On the contrary, from the present study, it may be concluded that annealing slightly improves the microstructure of both F2 and F3 samples.…”

Section: E G (T) Functions Of B2 F2 and F3 Samplesmentioning

confidence: 99%

Modification of the optical and elastic properties of TlGaSe₂ layered semiconductor produced by the memory effect

Cengiz,

Gören,

Sönmez

et al. 2023

Phys. Scr.

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A comparative analysis of the temperature behaviors of optical and elastic properties of TlGa Se 2 single crystals under a memory effect experimental condition are presented for the first time. A memory effect condition suggests that the sample is thermally annealed inside the incommensurate (INC) phase for a time interval the corresponding physical parameters is measured experimentally. From ultrasound velocity measurements, carried out before and after the thermal annealing process subjected to the sample, the noticeable changes in the temperature variation of the longitudinal ultrasonic wave velocity associated with the elastic constants C 33 of TlGa Se 2 due to the memory effect was detected. Our results reveal that thermal annealing performed at the INC - phase has some influence on the optical absorption of TlGa Se 2 crystals in the visible spectral region. We assumed that thermal annealing within INC - phase is accompanied with the appearance, inside TlGa Se 2 samples, a new quasiperiodic frozen structure formed from the intrinsic defects migrated into the lowest energy diffusion barriers of the INC - modulation wave. Such structural modulation is incommensurate with the underlying lattice of TlGa Se 2 and can lead to changes in the electronic band structure and the optical bandgaps of TlGa Se 2 .

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“…The slope of the ln(α) versus hv plot in the lower photon energy region was used for the calculation of E u (Urbach energy) of each paper sample [25]. The values of the Urbach energy E u [26], were calculated by taking the reciprocals of the slopes of the linear portion of the lnα versus hv curves in the lower photon energy regions. These values for all paper samples are given in Table 1.…”

Section: Measurement Of Brightnessmentioning

confidence: 99%

The Determination of Optical Properties of Papers and a Paper Board

Chryssou¹

2022

ACSR

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Reflection graphs of four paper samples were recorded at room temperature in the wavelength range 400-700nm. From the UV-Vis data and using the Kubelka-Munk equation we calculated the indirect band gap energies of four different paper samples. The indirect band gap for tissue paper was estimated to be 1.169844796675eV, that of copy paper A4 axion sample of 1.169844772981780eV, of velvet board of 1.169844786551eV, and finally of Α4 copy paper maestro of 1.1698447698146900eV. The indirect band gap value was higher for tissue paper and proceeded decreasing from velvet board to copy paper A4 axion, and finally copy paper A4 maestro. The band gap energy was determined using the Tauc method. The Urbach energy for tissue paper was calculated to be 199.23meV. The Urbach energy for axion Α4 copy paper was calculated to be 324.23meV. The Urbach energy for velvet board was calculated to be 71.12meV. And finally, the Urbach energy for Α4 copy paper maestro was calculated to be 341.17meV. The Urbach energy varied inversely to the band gap for all four paper samples.

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Cody disorder: Absorption-edge relationships in hydrogenated amorphous silicon

Cited by 9 publications

References 23 publications

Disorder and compositional dependences in Urbach-Martienssen tails in amorphous (GeTe)x(Sb2Te3)1−x alloys

Disorder and compositional dependences in Urbach-Martienssen tails in amorphous (GeTe)x(Sb2Te3)1−x alloys

Modification of the optical and elastic properties of TlGaSe₂ layered semiconductor produced by the memory effect

The Determination of Optical Properties of Papers and a Paper Board

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Cody disorder: Absorption-edge relationships in hydrogenated amorphous silicon

Cited by 9 publications

References 23 publications

Disorder and compositional dependences in Urbach-Martienssen tails in amorphous (GeTe)x(Sb2Te3)1−x alloys

Disorder and compositional dependences in Urbach-Martienssen tails in amorphous (GeTe)x(Sb2Te3)1−x alloys

Modification of the optical and elastic properties of TlGaSe2 layered semiconductor produced by the memory effect

The Determination of Optical Properties of Papers and a Paper Board

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Modification of the optical and elastic properties of TlGaSe₂ layered semiconductor produced by the memory effect