Chapter 4 Photoluminescence I: Theory

Bebb, H. Barry; Williams, E.W.

doi:10.1016/s0080-8784(08)62345-5

Cited by 118 publications

(70 citation statements)

References 90 publications

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“…The majority of these simplify the analysis by assuming either a parabolic dispersion for both the conduction and valence bands, or, even more simply, that the PL peak position is essentially equal to the transition energy. [15][16][17][18] Such simplifications ignore the effects of band nonparabolicity, despite the intrinsically nonparabolic nature of the conduction band in InAs being well documented. [19][20][21] Indeed, provided the experimental probe is insensitive to states far from the CBM, as is usually assumed in PL spectroscopy, such simplifications are often quite reasonable: it is a nontrivial task to include the corrections necessary to take account of intrinsic nonparabolicity.…”

Section: Analysis and Discussionmentioning

confidence: 99%

Photoluminescence of InNAs alloys: S-shaped temperature dependence and conduction-band nonparabolicity

et al. 2007

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Photoluminescence ͑PL͒ has been used as a means of unambiguously observing band gap reduction in InNAs epilayers grown by molecular beam epitaxy. The observed redshift in room temperature emission as a function of nitrogen concentration is in agreement with the predictions of the band anticrossing ͑BAC͒ model, as implemented with model parameters derived from tight-binding calculations. The temperature dependence of the emission from certain samples exhibits a signature non-Varshni-like behavior indicative of electron trapping in nitrogen-related localized states below the conduction-band edge, as predicted by the linear combination of isolated nitrogen states ͑LCINS͒ model. This non-Varshni-like behavior tends to grow more pronounced with increasing nitrogen content, but for the highest nitrogen concentration studied, the more familiar Varshni-like behavior is recovered. Although unexpected, this observation is found to be consistent with the BAC and LCINS models. With consideration given to the effects of conduction-band nonparabolicity on the emission line shapes, the BAC model parameters extracted from the measured PL transition energies are found to be in excellent agreement with the predictions of the aforementioned tight-binding calculations.

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Section: Analysis and Discussionmentioning

confidence: 99%

Photoluminescence of InNAs alloys: S-shaped temperature dependence and conduction-band nonparabolicity

et al. 2007

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“…For example, the efficiency of solar cells is limited by non-radiative recombination occurring in the bulk via defect states or at the surfaces via surface states. PL spectroscopy also gives us information on band bending [33], surface related transitions [34] and near-surface bulk properties [35]. Thus, Raman and PL spectroscopy yield structural and dynamic information on materials at the molecular level.…”

Section: B Photoluminescencementioning

confidence: 99%

A nondestructive tool for nanomaterials: Raman and photoluminescence spectroscopy

Singha

Dhar

Roy

2005

American Journal of Physics

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Modern materials science requires efficient processing and characterization techniques for low dimensional systems. Raman spectroscopy is an important non-destructive tool, which provides enormous information on these materials. This understanding is not only interesting in its own right from a physicist's point of view, but can also be of considerable importance in optoelectronics and device applications of these materials in nanotechnology. The commercial Raman spectrometers are quite expensive. In this article, we have presented a relatively less expensive set-up with homebuilt collection optics attachment. The details of the instrumentation have been described. Studies on four classes of nanostructures -Ge nanoparticles, porous silicon (nanowire), carbon nanotubes and 2D InGaAs quantum layers, demonstrate that this unit can be of use in teaching and research on nanomaterials.

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“…However, currently the 11 knowledge of such properties mostly comes from theoretical studies based on density 12 functional theory [5,6]. To become a reliable support for technology developers these 13 theoretical findings should be verified by experimental evidence [2]. 14 The main drawback of CZTSe-based solar cells is thought to be the small value of the 15 open circuit voltage (V OC ) [2,7].…”

Section: Introductionmentioning

confidence: 99%

“…It is important to find the 22 particular technological parameters which can control the randomisation. 23 One of the most sensitive spectroscopic techniques to study the electronic properties of 24 semiconductors in general and in particular defects with energy levels in the bandgap is 25 photoluminescence (PL) [13]. The PL spectra of CZTSe films with small copper excess 1 reveal rather narrow peaks assigned to donor-acceptor pair (DAP) recombination mechanisms 2 and excitonic features [14].…”

Section: Introductionmentioning

confidence: 99%

Influence of the copper content on the optical properties of CZTSe thin films

Yakushev

Сулимов

Márquez-Prieto

et al. 2017

Solar Energy Materials and Solar Cells

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We present an optical spectroscopy study of Cu 2 ZnSnSe 4 (CZTSe) thin films deposited on Mo/glass substrates. The [Cu]/[Zn+Sn] ratio in these films varies from nearly stoichiometric to strongly Cu deficient and Zn rich. Increasing Cu deficiency and Zn excess widens the bandgap E g , determined using photoluminescence excitation (PLE) at 4.2 K, from 0.99 eV to 1.03 eV and blue shifts the dominant band in the photoluminescence (PL) spectra from 0.83 eV to 0.95 eV. The PL spectra of the near stoichiometric film reveal two bands: a dominant band centred at 0.83 eV and a lower intensity one at 0.93 eV. The temperature and excitation intensity dependence of the PL spectra help to identify the recombination mechanisms of the observed emission bands as free-to-bound: recombination of free electrons with holes localised at acceptors affected by randomly distributed potential fluctuations. Both the mean 2 depth of such fluctuations, determined by analysing the shape of the dominant bands, and the broadening energy, estimated from the PLE spectra, become smaller with increasing Cu deficiency and Zn excess which also widens E g due to an improved ordering of the Cu/Zn atoms. These changes in the elemental composition induce a significant blue shift of the PL bands exceeding the E g widening. This is attributed to a change of the dominant acceptor for a shallow one, and is beneficial for the solar cell performance. Film regions with a higher degree of Cu/Zn ordering are present in the near stoichiometric film generating the second PL band at 0.93 eV.

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Chapter 4 Photoluminescence I: Theory

Cited by 118 publications

References 90 publications

Photoluminescence of InNAs alloys: S-shaped temperature dependence and conduction-band nonparabolicity

Photoluminescence of InNAs alloys: S-shaped temperature dependence and conduction-band nonparabolicity

A nondestructive tool for nanomaterials: Raman and photoluminescence spectroscopy

Influence of the copper content on the optical properties of CZTSe thin films

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