Optical Properties of Intrinsic Excitons in Bulk Semiconductors

Klingshirn, C.

doi:10.1007/978-3-642-28362-8_13

Cited by 3 publications

(3 citation statements)

References 176 publications

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“…The temperature-dependent fwhm for Cs 3 Sb 2 Br 9 IPQDs is shown in Figure d. The PL spectra could be fitted by adapting the independent Boson model: where Γ 0 is the inhomogeneous broadening contribution, σ and Γ OP describe the interactions of exciton–acoustic phonon interaction and exciton–optical phonon interaction contributions to the fwhm broadening, respectively, and ℏω OP is the optical phonon energy. At low temperature, the first term Γ 0 was the dominant contributor to Γ( T ).…”

Section: Resultsmentioning

confidence: 99%

High Quantum Yield Blue Emission from Lead-Free Inorganic Antimony Halide Perovskite Colloidal Quantum Dots

et al. 2017

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Colloidal quantum dots (QDs) of lead halide perovskite have recently received great attention owing to their remarkable performances in optoelectronic applications. However, their wide applications are hindered from toxic lead element, which is not environment- and consumer-friendly. Herein, we utilized heterovalent substitution of divalent lead (Pb) with trivalent antimony (Sb) to synthesize stable and brightly luminescent CsSbBr QDs. The lead-free, full-inorganic QDs were fabricated by a modified ligand-assisted reprecipitation strategy. A photoluminescence quantum yield (PLQY) was determined to be 46% at 410 nm, which was superior to that of other reported halide perovskite QDs. The PL enhancement mechanism was unraveled by surface composition derived quantum-well band structure and their large exciton binding energy. The Br-rich surface and the observed 530 meV exciton binding energy were proposed to guarantee the efficient radiative recombination. In addition, we can also tune the inorganic perovskite QD (CsSbX) emission wavelength from 370 to 560 nm via anion exchange reactions. The developed full-inorganic lead-free Sb-perovskite QDs with high PLQY and stable emission promise great potential for efficient emission candidates.

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Section: Resultsmentioning

confidence: 99%

High Quantum Yield Blue Emission from Lead-Free Inorganic Antimony Halide Perovskite Colloidal Quantum Dots

et al. 2017

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“…Given that the inelastic scattering loss in the RP and DJ perovskites is extremely weak, the absorption coefficient α can be deduced from the relation of α = 4πκ/λ, and the calculated results are plotted in Figures d and e). The ground-state exciton absorption peak as an observed value between ∼1.2 × 10 4 cm –1 and up to ∼5.1 × 10 5 cm –1 , which is one order of magnitude larger than the exciton features in MAPbI 3 (3D perovskites) and GaAs. , Again, this result reflects the low-dimensional character of 2D RP and DJ perovskites where the oscillator strength is largely concentrated in the exciton ground-state . Compared to the relatively flat band-edge absorption features of MAPbI 3 and traditional III–V semiconductor GaAs, the steplike α of RP ( n = 1) strongly suggests 2D nature of the density of state akin to GaAs quantum wells .…”

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confidence: 88%

“…56,57 Again, this result reflects the lowdimensional character of 2D RP and DJ perovskites where the oscillator strength is largely concentrated in the exciton ground-state. 58 Compared to the relatively flat band-edge absorption features of MAPbI 3 and traditional III−V semiconductor GaAs, 59 the steplike α of RP (n = 1) strongly suggests 2D nature of the density of state akin to GaAs quantum wells. 60 The excitons in 2D RP and DJ perovskites can be regarded as strongly bound Wannier excitons, because of the significant quantum confinement and dielectric confinement effects.…”

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confidence: 99%

Determination of Dielectric Functions and Exciton Oscillator Strength of Two-Dimensional Hybrid Perovskites

Song

Hou

Wang

et al. 2020

ACS Materials Lett.

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hybrid organic inorganic perovskite (HOIP) semiconductors have attracted widespread attention as a platform of next-generation optoelectronic devices benefiting from their naturally occurring and tunable multiple quantum-well-like (QW-like) structures, which enable a wide range of physical properties. Determining the intrinsic optical/ electronic properties of 2D HOIPs is extremely important for further utility in photonic and optoelectronic devices. Here, we obtain the optical dielectric functions, complex refractive indices, and complex optical conductivities of both Ruddlesden−Popper (RP) and Dion−Jacobson (DJ) phases of 2D HOIPs, as a function of the perovskite QW thickness via spectroscopic ellipsometry over a broad energy range of 0.73−3.34 eV. We identify a series of feature peaks in the dielectric functions, and we explain the evolution of ground-state exciton peak with unit-cell thickness and changing excitonic confinement. We observe extraordinary values of optical extinction and electric loss tangents at the primary excitonic resonances and provide their detailed comparison with other known excitonic materials. Our study is expected to lay the foundation for understanding optical properties of pure-phase 2D HOIPs, which are critical and imperative for the accurate modelling of their photonic and optoelectronic devices.

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Influence of oxygen impurities in generating ferromagnetism in GaN doped with Mn, Fe, and Cr

Mendoza-Rodarte,

Maestre,

Camacho-López

et al. 2024

J Mater Sci: Mater Electron

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We report the influence of oxygen impurities in generating ferromagnetism in GaN doped with Mn, Fe, and Cr through superexchange involving Mn–O–Mn, Fe–O–Fe, and Cr–N–Cr atomic configurations. Density Functional Theory (DFT) calculations demonstrated that these configurations originate within $${V}_{\text{Ga}}-{O}_{\text{N}}$$ V Ga - O N complex defects by incorporating Mn2+, Fe2+, and Cr3+ ions into gallium vacancies ($${V}_{\text{Ga}}$$ V Ga ) sites promoted by the presence of oxygen as a substitutional impurity ($${O}_{\text{N}}$$ O N ). These co-doped GaN microstructures were synthesized using the thermal evaporation method. Cathodoluminescence (CL) and photoluminescence (PL) measurements confirmed the presence of $${V}_{\text{Ga}}-{O}_{\text{N}}$$ V Ga - O N complex defects in all GaN-grown samples. X-ray photoelectron spectroscopy (XPS) measurements confirmed the successful incorporation of Mn2+, Fe2+, and Cr3+ ions in GaN samples. SQUID measurements demonstrated room-temperature ferromagnetism with respective saturation magnetization (Ms) and coercive field (Hc) values of ± 1.5 × 10−5 emu and 4 mT for GaN:O,Mn, ± 4.4 × 10−5 emu and 2.6 mT for GaN:O,Fe, and ± 1.7 × 10−5 emu and 2.6 mT for GaN:O,Cr.

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Optical Properties of Intrinsic Excitons in Bulk Semiconductors

Cited by 3 publications

References 176 publications

High Quantum Yield Blue Emission from Lead-Free Inorganic Antimony Halide Perovskite Colloidal Quantum Dots

High Quantum Yield Blue Emission from Lead-Free Inorganic Antimony Halide Perovskite Colloidal Quantum Dots

Determination of Dielectric Functions and Exciton Oscillator Strength of Two-Dimensional Hybrid Perovskites

Influence of oxygen impurities in generating ferromagnetism in GaN doped with Mn, Fe, and Cr

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