Inherent photoluminescence Stokes shift in GaAs

Singh, Akhilesh Kumar; Barik, Puspendu; Xi, Haowen; Bhowmick, Mithun

doi:10.1364/ol.40.002580

Cited by 21 publications

(15 citation statements)

References 16 publications

(36 reference statements)

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“…In this section, we demonstrate further evidence that the JDOS, which is defined with Equations ( 5) and (6), results in accurate E g values. For this purpose, we retrieved absorption data at room temperature from the literature, and performed fits for crystalline InP [7], InAs [8], InSb [9], and GaAs [10].…”

Section: New Results and Established Usage Of The Modified Urbach Rulesupporting

confidence: 53%

“…For this purpose, we retrieved absorption data at room temperature from the literature, and performed fits for crystalline InP [7], InAs [8], InSb [9], and GaAs [10]. The symbols in Figures 1-4 represent the measurements, and the solid lines fits with Equations ( 5) and (6). All fits are carried out with kT = 0.025 eV, and Table 1 lists the fit parameters.…”

Section: New Results and Established Usage Of The Modified Urbach Rulementioning

confidence: 99%

“…In much more recent publications, by fitting the highly transparent part of the transmission spectra of ZnO [3] and GaAs [6], we established that E ch = E g , i.e., Equation (3) transforms to:…”

Section: The Modified Urbach Rulementioning

confidence: 94%

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Optical Bandgap Definition via a Modified Form of Urbach’s Rule

Bhowmick

2021

Materials

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We are reporting an esoteric method to determine the optical bandgap of direct gap materials by employing Urbach’s rule. The latter, which describes the slope of the band tail absorption in semiconductors, in its original version, cannot be employed to pinpoint the optical bandgap. Herein, however, we show that a modified form of Urbach’s rule defines the optical bandgap, and therefore, enables the accurate determination of the optical bandgap energy, which turns out to be identical with the threshold energy for the band tail absorption. The model further produces an explicit expression for the absorption coefficient at the optical bandgap energy.

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Section: New Results and Established Usage Of The Modified Urbach Rulesupporting

confidence: 53%

Section: New Results and Established Usage Of The Modified Urbach Rulementioning

confidence: 99%

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Optical Bandgap Definition via a Modified Form of Urbach’s Rule

Bhowmick

2021

Materials

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“…From polaron theory, Fan derived Eq. (6) for the emission Stokes shift (from the band edge) of recombining free carriers coupled to harmonic LO phonons 44,45 . Here E LO is the LO phonon energy, and the other symbols have their usual meaning.…”

Section: Resultsmentioning

confidence: 99%

Dynamic emission Stokes shift and liquid-like dielectric solvation of band edge carriers in lead-halide perovskites

et al. 2019

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Lead-halide perovskites have emerged as promising materials for photovoltaic and optoelectronic applications. Their significantly anharmonic lattice motion, in contrast to conventional harmonic semiconductors, presents a conceptual challenge in understanding the genesis of their exceptional optoelectronic properties. Here we report a strongly temperature dependent luminescence Stokes shift in the electronic spectra of both hybrid and inorganic lead-bromide perovskite single crystals. This behavior stands in stark contrast to that exhibited by more conventional crystalline semiconductors. We correlate the electronic spectra with the anti-Stokes and Stokes Raman vibrational spectra. Dielectric solvation theories, originally developed for excited molecules dissolved in polar liquids, reproduce our experimental observations. Our approach, which invokes a classical Debye-like relaxation process, captures the dielectric response originating from the incipient anharmonicity of the LO phonon at about 20 meV (160 cm−1) in the lead-bromide framework. We reconcile this liquid-like model incorporating thermally-activated dielectric solvation with more standard solid-state theories of the emission Stokes shift in crystalline semiconductors.

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“…For example, while measuring transmission spectra from a thin film, or a layered material, interference effects are observed as oscillations in the spectra [25]. Sometimes, the effect is welcome when the film thickness is unknown and needs to be measured [26,27]. At other times the interference effect makes it difficult to efficiently fit the spectra to get important band parameters in solids [28].…”

Section: Introductionmentioning

confidence: 99%