Effect of size confinement on CdSe nanocrystals in a GeO2 glass matrix characterized by photoacoustic spectroscopy

Toyoda, Taro; Arae, Dai; Shen, Qing

doi:10.1016/s0921-4526(02)00547-1

Cited by 3 publications

(3 citation statements)

References 6 publications

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“…The absence of excitonic peaks in the photoacoustic spectrum requires further, more detailed discussion. This observation is consistent with previous reports on CdSe QDs deposited on different transparent oxide substrates, − where the authors attributed the signal saturation to high sensitivity of this method to a low absorption coefficient in comparison with regular transmission measurements. Absorption characteristic of InGaN/GaN quantum wells were also studied using photoacoustic spectra .…”

supporting

confidence: 93%

“…Despite other band gap determination methods being developed, good agreement of the knee method results with the transition energies obtained with modulation spectroscopy, known to be a state-of-the-art characterization technique of semiconductor compounds, confirms its usefulness . More importantly, this approach has been previously followed to study low-dimensional structures, including QDs. − …”

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confidence: 79%

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Exciton Binding Energy of Two-Dimensional Highly Luminescent Colloidal Nanostructures Determined from Combined Optical and Photoacoustic Spectroscopies

Zelewski

Nawrot

Żak

et al. 2019

J. Phys. Chem. Lett.

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Reduced dimensionality of structures such as 0D quantum dots, 1D nanorods, and 2D nanoplatelets is predicted to favor the creation of tightly bound excitons stable at room temperature, making experimental determination of the exciton binding energy (R x ) crucial for evaluating the performance of semiconductor nanoparticles. We propose a fully optical approach for R x determination based on a complementary combination of photoacoustic and transmission spectra, using 5.5, 4.5, and 3.5 ML CdSe nanoplatelets as a benchmark system. The absence of excitonic features in photoacoustic spectra allows for probing the band-to-band transition, leading to the band gap determination. Such an unusual effect is explained by efficient re-emission of the absorbed radiation typical for high quantum yield structures, keeping the crystal lattice from excess phonon generation. The determined exciton binding energy for CdSe nanoplatelets ranges from 130 to 230 meV, confirming the presence of robust excitons in highly confined 2D systems.

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confidence: 93%

mentioning

confidence: 79%

Exciton Binding Energy of Two-Dimensional Highly Luminescent Colloidal Nanostructures Determined from Combined Optical and Photoacoustic Spectroscopies

Zelewski

Nawrot

Żak

et al. 2019

J. Phys. Chem. Lett.

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“…The observed trend in the thermal diffusivities of gadolinium doped cerium oxide compares very well with the literature [7,8]. Then, effective thermal conductivity (k eff ) can be determined by the following relation…”

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confidence: 85%

Thermal properties of 15-mol% gadolinia doped ceria thin films prepared by pulsed laser ablation

Muthukkumaran

Kuppusami

Srinivasan³

et al. 2007

Ionics

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Thermal properties of 15-mol% gadolinia doped ceria thin films (Ce 0.85 Gd 0.15 O 1.925 ) prepared by pulsed laser ablation on silicon substrates in the temperature range 473-973 K are presented. Thermal diffusivities and thermal conductivities were evaluated using photoacoustic spectroscopy. The influence of grain size on thermal properties of the films as a function of deposition temperature is studied. It is observed that the thermal diffusivity and the conductivity of these films decreases up to 873 K and then increases with substrate temperatures. The thermal properties obtained in these films are discussed on the basis of influence of grain size on phonon scattering.

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Quantum confinement effects in variable band-gap GaNxAs1−x thin films studied by photoacoustic spectroscopy

Cardona-Bedoya

Cruz‐Orea

Tomas-Velazquez

et al. 2003

Review of Scientific Instruments

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By using the magnetron radio frequency (rf) sputtering deposition technique we have grown a new family of III–V nitride semiconductors: GaNxAs1−x thin films with nanocrystalline grain sizes and different N concentrations obtained by controlling the rf power used in the growth process. We have used the photoacoustic spectroscopy to measure the absorption edge behavior for the series of GaNAs films grown with different stoichiometries. The absorption spectra show a clear shift to higher energies as the N concentration increases; also, very remarkable shoulders in these spectra are clear evidence of the presence of optical transitions between energy levels produced by the quantum confinement effects that takes place because the average grain sizes (16 Å) are comparable to the exciton Bohr radius for GaN (28 Å). We discuss the quantum confinement regime for this case, and how information concerning the hole effective mass can be obtained by comparing a theoretical model to the experimentally observed transitions between the quantized electronic levels.

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Effect of size confinement on CdSe nanocrystals in a GeO2 glass matrix characterized by photoacoustic spectroscopy

Cited by 3 publications

References 6 publications

Exciton Binding Energy of Two-Dimensional Highly Luminescent Colloidal Nanostructures Determined from Combined Optical and Photoacoustic Spectroscopies

Exciton Binding Energy of Two-Dimensional Highly Luminescent Colloidal Nanostructures Determined from Combined Optical and Photoacoustic Spectroscopies

Thermal properties of 15-mol% gadolinia doped ceria thin films prepared by pulsed laser ablation

Quantum confinement effects in variable band-gap GaNxAs1−x thin films studied by photoacoustic spectroscopy

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