Impact of PbS quantum dots on GaAs photoluminescence

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

doi:10.1117/12.2572833

Cited by 5 publications

(10 citation statements)

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“…From the energy point of view, condition in Equation (7) means that in the material under consideration, the size quantization energy of charge carriers in any of the X , Y , and Z directions is much greater than the energy of the Coulomb interaction between an electron and a hole [ 53 , 54 , 55 ]. Approximating the NPL in the X , Y , Z directions by an infinitely deep rectangular potential, neglecting the Coulomb interaction between an electron and a hole, for the envelope wave functions and the energy spectrum of charge carriers in the CdSe NPL in the corresponding directions, we obtain:

…”

Section: Optical Transitions In Semiconductor Nanoplateletsmentioning

confidence: 99%

“…The corresponding characteristics of the PbS NPL differ significantly from those of CdSe. In a bulk sample of PbS, the Bohr radius is 18–20 nm,

3968 meV [ 48 , 55 , 59 ] with thicknesses of 1.2–4.6 nm and from several nanometers to the hundreds in lateral size [ 23 , 59 , 60 , 61 , 62 ]. In this case, the exciton effects can be considered within the framework of perturbation theory.…”

Section: Optical Transitions In Semiconductor Nanoplateletsmentioning

confidence: 99%

“…In weak quantization mode, it is assumed that the following conditions are satisfied for the geometric dimensions of the NPL [ 53 , 54 , 55 ]:

…”

Section: Optical Transitions In Semiconductor Nanoplateletsmentioning

confidence: 99%

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Exciton States and Optical Absorption in CdSe and PbS Nanoplatelets

et al. 2022

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The exciton states and their influence on the optical absorption spectrum of CdSe and PbS nanoplatelets (NPLs) are considered theoretically in this paper. The problem is discussed in cases of strong, intermediate, and weak size quantization regimes of charge carrier motion in NPLs. For each size quantization regime, the corresponding potential that adequately describes the electron–hole interaction in this mode of space quantization of charge carriers is chosen. The single-particle energy spectra and corresponding wave functions for strong intermediate and weak size quantization regimes have been revealed. The dependence of material parameters on the number of monolayers in the sample has been considered. The related selection rules and the dependence of the absorption coefficient on the frequency and polarization direction of the incident light wave were obtained. The interband transition threshold energy dependencies were obtained for each size quantization regime. The effect of dielectric coefficient mismatch and different models of electron–hole interaction potentials have been studied in CdSe and PbS NPLs. It is also shown that with an increase in the linear dimensions of the structure, the threshold frequency of absorption decreases. The binding energies and absorption coefficient results for NPL with different thicknesses agree with the experimental data. The values of the absorption exciton peaks measured experimentally are close to our calculated values for CdSe and PbS samples.

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…”

Section: Optical Transitions In Semiconductor Nanoplateletsmentioning

confidence: 99%

“…The corresponding characteristics of the PbS NPL differ significantly from those of CdSe. In a bulk sample of PbS, the Bohr radius is 18–20 nm,

Section: Optical Transitions In Semiconductor Nanoplateletsmentioning

confidence: 99%

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Exciton States and Optical Absorption in CdSe and PbS Nanoplatelets

et al. 2022

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“…It is approximated that the maximum exciton binding energy is four times the exciton binding energy in bulk materials, E bulk [ 46 ]. In the case of PbS, the exciton binding energy E bulk (PbS) is 3.968 meV [ 47 ]. Thus, for an electron effective mass of 0.085 m0 ( m0 is the free electron mass), equal to hole effective mass [ 48 , 49 ], and a dielectric constant of 17.5 [ 50 ], the maximum exciton binding energy of QDs is 15.872 meV.…”

Section: Resultsmentioning

confidence: 99%

“…The PbS nanoparticle size, d , determined from Equation (2), based on Equation (3), using E g = 1.004 eV, is about 7.72 nm, close to the value determined by XRD analysis, 7.99 nm. Thus, the quantum confinement effect, which is the dependency of the band gap value on the quantum dots size, is valid in the case of PbS-doped film, because the nanoparticle size is lower than the Bohr radius of the exciton in PbS, 18 nm [ 46 , 47 ].…”

Section: Resultsmentioning

confidence: 99%

Nanostructured PbS-Doped Inorganic Film Synthesized by Sol-Gel Route

et al. 2022

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IV-VI semiconductor quantum dots embedded into an inorganic matrix represent nanostructured composite materials with potential application in temperature sensor systems. This study explores the optical, structural, and morphological properties of a novel PbS quantum dots (QDs)-doped inorganic thin film belonging to the Al2O3-SiO2-P2O5 system. The film was synthesized by the sol-gel method, spin coating technique, starting from a precursor solution deposited on a glass substrate in a multilayer process, followed by drying of each deposited layer. Crystalline PbS QDs embedded in the inorganic vitreous host matrix formed a nanocomposite material. Specific investigations such as X-ray diffraction (XRD), optical absorbance in the ultraviolet (UV)-visible (Vis)-near infrared (NIR) domain, NIR luminescence, Raman spectroscopy, scanning electron microscopy–energy dispersive X-ray (SEM-EDX), and atomic force microscopy (AFM) were used to obtain a comprehensive characterization of the deposited film. The dimensions of the PbS nanocrystallite phase were corroborated by XRD, SEM-EDX, and AFM results. The luminescence band from 1400 nm follows the luminescence peak of the precursor solution and that of the dopant solution. The emission of the PbS-doped film in the NIR domain is a premise for potential application in temperature sensing systems.

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All-optical switch based on PbS quantum dots

Bhowmick

Singh

Barik

et al. 2021

Applied Physics Letters

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We hetero-paired a ∼200 nm thin film consisting of colloidal 2.5 nm PbS quantum dots deposited on semi-insulating GaAs. By exciting the thin film with laser pulses (26 ps, 10 Hz) at 1064 nm, we observed the two-photon stimulated emission of the PbS quantum dots and the GaAs host. At a certain intensity of the optical stimulus, the absorption capability of the quantum dots collectively saturates, and more photons of the laser beam reach the GaAs host, causing a bistable-like up-switch in the GaAs photoluminescence intensity. The work further addresses the determination of the two-photon absorption coefficient, which was found to be 8.6 × 10−6 m/W.

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Impact of PbS quantum dots on GaAs photoluminescence

Cited by 5 publications

References 0 publications

Exciton States and Optical Absorption in CdSe and PbS Nanoplatelets

Exciton States and Optical Absorption in CdSe and PbS Nanoplatelets

Nanostructured PbS-Doped Inorganic Film Synthesized by Sol-Gel Route

All-optical switch based on PbS quantum dots

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