Toward a Unified Theory of Urbach's Rule and Exponential Absorption Edges

Dow, John D.; Redfield, David

doi:10.1103/physrevb.5.594

Cited by 701 publications

(232 citation statements)

References 65 publications

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“…Thus, there are no incoming fluxes considered in Eqs. (11) and (12) since the dark photon flux has zero divergence and is treated as a constant background, assuming that the sample is in thermal equilibrium with its surrounding environment. For exactness, according to the previous PL definition, the dark emission contribution to R sp with Δμ ¼ 0 should be removed, but, for PL measurements, fexp ½ðℏω − ΔμÞ= k B T − 1g −1 ≫ ½exp ðℏω=k B TÞ − 1 −1 , and such a correction is disregarded.…”

Section: B Light Propagationmentioning

confidence: 99%

“…Band tailing in semiconductors may occur at both conduction and valence band edges in a nonsymmetrical way [8]. If the band tails are described by Urbach behavior [9] [exponential decrease of the density of states (DOS) from the band edges towards midgap], which is observed in most materials [10][11][12][13][14], the extension of the joint DOS below the band-gap energy is determined by the band edge, which shows the broadest extension into the band gap [15].…”

Section: Introductionmentioning

confidence: 99%

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Absorption Coefficient of a Semiconductor Thin Film from Photoluminescence

et al. 2018

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The photoluminescence (PL) of semiconductors can be used to determine their absorption coefficient (α) using Planck's generalized law. The standard method, suitable only for self-supported thick samples, like wafers, is extended to multilayer thin films by means of the transfer-matrix method to include the effect of the substrate and optional front layers. α values measured on various thin-film solar-cell absorbers by both PL and photothermal deflection spectroscopy (PDS) show good agreement. PL measurements are extremely sensitive to the semiconductor absorption and allow us to advantageously circumvent parasitic absorption from the substrate; thus, α can be accurately determined down to very low values, allowing us to investigate deep band tails with a higher dynamic range than in any other method, including spectrophotometry and PDS.

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Section: B Light Propagationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Absorption Coefficient of a Semiconductor Thin Film from Photoluminescence

et al. 2018

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“…Lead phosphate glasses possess enhanced optical non-linearity due to the high polarizability of Pb 2+ ions in glass matrices. Electrostatic interaction between transition metal ions and the highly excited Pb 4+ ions is also known to cause this result [48].…”

Section: Resultsmentioning

confidence: 99%

Structural Investigations of Cr3+ Ions Doped Alkali Lead Zinc Phosphate Glasses

Sastry¹

2015

IJIRSET

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Lead zinc phosphate glasses containing 0.1% transition metal ion Cr 3+ were prepared by melt quenching technique and their amorphous nature confirmed by X-Ray diffraction. The covalent bond nature of Cr 3+ ions with octahedral symmetry in glass network was established through Electron Paramagnetic Resonance and optical absorption spectroscopic studies. Endothermic dip for glass transition temperature (T g ) at about 410 0 C and an exothermic peak subsisted from thermal studies were obtained. De-polymerization of host glass network due to addition of alkali content to the glass matrix, has turned as a strong candidate for nonlinear optical laser applications.

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“…While science has good knowledge on the magnitude of semiconductor bandgaps, there is not much information regarding the sharpness of the band edges. Although there are no good direct measurements of the band edge density of states, we can infer it from optical [14] and electronic measurements [15].…”

Section: Energy Filtering Switching Mechanismmentioning

confidence: 99%