Photoluminescence studies of GaAs/AlAs short period superlattices

Jones, E. D.; Drummond, T. J.; Hjalmarson, H.P.; Schirber, J. E.

doi:10.1016/0749-6036(88)90041-9

Cited by 9 publications

(3 citation statements)

References 18 publications

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“…Unlike the artificially constructed quantum well structures of the classical III−V semiconductors (for example, the GaAs/ AlAs/GaAs heterostructures) 99 where the excitons are observable only at low temperature, the excitons in BA 2 (MA) n−1 Pb n I 3n+1 are stable at room temperature. 58 As it has been suggested, 41 the stable excitons in the 2D perovskites are due to the Coulombic charge screening effect, which results from the charged nature of the perovskite {MA n−1 Pb n I 3n+1 } 2− slabs as opposed to the neutral covalent framework of GaAs-based quantum well structures.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Ruddlesden–Popper Hybrid Lead Iodide Perovskite 2D Homologous Semiconductors

Cao²,

et al. 2016

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The hybrid two-dimensional (2D) halide perovskites have recently drawn significant interest because they can serve as excellent photoabsorbers in perovskite solar cells. Here we present the large scale synthesis, crystal structure, and optical characterization of the 2D (CH 3 (CH 2 ) 3 NH 3 ) 2 (CH 3 NH 3 ) n−1 Pb n I 3n+1 (n = 1, 2, 3, 4, ∞) perovskites, a family of layered compounds with tunable semiconductor characteristics. These materials consist of well-defined inorganic perovskite layers intercalated with bulky butylammonium cations that act as spacers between these fragments, adopting the crystal structure of the Ruddlesden−Popper type. We find that the perovskite thickness (n) can be synthetically controlled by adjusting the ratio between the spacer cation and the small organic cation, thus allowing the isolation of compounds in pure form and large scale. The orthorhombic crystal structures of (CH 3 (CH 2 ) 3 NH 3 ) 2 (CH 3 NH 3 )-Pb 2 I 7 (n = 2, Cc2m; a = 8.9470(4), b = 39.347(2) Å, c = 8.8589(6)), (CH 3 (CH 2 ) 3 NH 3 ) 2 (CH 3 NH 3 ) 2 Pb 3 I 10 (n = 3, C2cb; a = 8.9275( 6), b = 51.959(4) Å, c = 8.8777(6)), and (CH 3 (CH 2 ) 3 NH 3 ) 2 (CH 3 NH 3 ) 3 Pb 4 I 13 (n = 4, Cc2m; a = 8.9274(4), b = 64.383(4) Å, c = 8.8816(4)) have been solved by single-crystal X-ray diffraction and are reported here for the first time. The compounds are noncentrosymmetric, as supported by measurements of the nonlinear optical properties of the compounds and density functional theory (DFT) calculations. The band gaps of the series change progressively between 2.43 eV for the n = 1 member to 1.50 eV for the n = ∞ adopting intermediate values of 2.17 eV (n = 2), 2.03 eV (n = 3), and 1.91 eV (n = 4) for those between the two compositional extrema. DFT calculations confirm this experimental trend and predict a direct band gap for all the members of the Ruddlesden− Popper series. The estimated effective masses have values of m h = 0.14 m 0 and m e = 0.08 m 0 for holes and electrons, respectively, and are found to be nearly composition independent. The band gaps of higher n members indicate that these compounds can be used as efficient light absorbers in solar cells, which offer better solution processability and good environmental stability. The compounds exhibit intense room-temperature photoluminescence with emission wavelengths consistent with their energy gaps, 2.35 eV (n = 1), 2.12 eV (n = 2), 2.01 eV (n = 3), and 1.90 eV (n = 4) and point to their potential use in light-emitting diodes. In addition, owing to the low dimensionality and the difference in dielectric properties between the organic spacers and the inorganic perovskite layers, these compounds are naturally occurring multiple quantum well structures, which give rise to stable excitons at room temperature.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Ruddlesden–Popper Hybrid Lead Iodide Perovskite 2D Homologous Semiconductors

Cao²,

et al. 2016

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“…The excitons are bound in the built-in electric field between the positive organic layer and the negative inorganic layer. For the III-V group's semiconductor, such as heterojunction GaAs/AlAs/GaAs, excitons can only exist stably at low temperature, rather than room temperature [56]. Conversely, excitons in 2D perovskite can exist stably at room temperature due to the Cullen medium shielding effect [57].…”

Section: Exciton Confinement and Photoexcitation Transfermentioning

confidence: 99%

Two-dimensional organic-inorganic hybrid perovskite: from material properties to device applications

Cai

Cheng

et al. 2018

Sci. China Mater.

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“…Ma et al (2018) stated that the 2D perovskite could be served as a quantum-well structure due to its spatial-confinement layered nanostructures with the organic layers acting as barriers and a built-in electric filed between the negative and the positive inorganic layer [128]. It is generally known that the excitons for III-V group's semiconductors like GaAs, GaAs and AlAs could only exist stably at extra low temperature [168], while excitons of 2D perovskite can be observed at room temperature because of the Coulomb medium shielding effect [169]. [192−194] 3D MAPbI3−xCl3 55 ± 20 [195] 3D CsPbBr3 42 [196] 2D (C6H5C2H4NH3)2PbI4 ~ 220 [163] 2D (C4H9NH3)2PbBr4 480 [197] 2D (R)2PbnBr4 (R = BA, PEA, PBA) 310-320 [198] Quasi-2D (MAPbI3)(C6H5C2H4NH3)2PbI4 170 [163] Quasi-2D CsPbX3 NPLs 120 [199] There may be a mismatch of dielectric-constant between inorganic layer and organic layer, resulting in enhanced exciton performance in 2D perovskite.…”

Section: Quantum Confinement and Exciton Propertiesmentioning

confidence: 99%

Two-dimensional materials for light emitting applications: Achievement, challenge and future perspectives

et al. 2020

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The two-dimensional (2D) materials have been widely developed recently in material characteristics with advanced optical and electrical properties, and they have been extensively studied as candidates for the next generation of optoelectronic devices. This review will mainly focus on the preparation methods and the light emitting applications of 2D transition metal dichalcogenides (TMDs), 2D black phosphorene (BP) and 2D perovskites. The review will first introduce the preparation methods for TMDs and BP. Due to the variations of band structure, exciton binding energies and light-matter interaction in TMDs and BP, the different light emitting devices (LEDs) designs based on TMDs and BP will be discussed and summarized. Then the review will turn the focus to 2D perovskites, starting with a description of the preparation methods for the different structural perovskites. In order to review and summarize the achievements of 2D perovskites-based LEDs, the high efficiency perovskites LEDs are discussed. Finally, the review will present challenges, opportunities, and outlook for the future development of 2D materials-based light emitting applications.

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Photoluminescence studies of GaAs/AlAs short period superlattices

Cited by 9 publications

References 18 publications

Ruddlesden–Popper Hybrid Lead Iodide Perovskite 2D Homologous Semiconductors

Ruddlesden–Popper Hybrid Lead Iodide Perovskite 2D Homologous Semiconductors

Two-dimensional organic-inorganic hybrid perovskite: from material properties to device applications

Two-dimensional materials for light emitting applications: Achievement, challenge and future perspectives

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