Hydrostatic pressure and conduction band non-parabolicity effects on the impurity binding energy in a spherical quantum dot

Sivakami, A.; Mahendran, M.

doi:10.1016/j.physb.2009.12.008

Cited by 22 publications

(8 citation statements)

References 19 publications

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“…This discrepancy can be explained as follows: (1) the electron is spatially more confined than the size decrease of the QDs suggests, which results in increasing the binding energy of the exciton and band gap energy. However, previous research reported that any further decrease in the size of the QDs leads to the reduction of the exciton binding energy and leakage of electrons out of the QDs. − In the case of Sn 12 , the band gap energy is assumed to be lower than that of the theoretical model because the leakage of the electron significantly occurs around this size. (2) The periodic potential of the tin oxide crystal disappears with the decreasing size, and it is assumed that the Sn 12 oxide QDs might contain no crystal moiety as described by the DFT calculations.…”

Section: Resultsmentioning

confidence: 99%

Dendrimer-Templated Synthesis and Characterization of Tin Oxide Quantum Dots Deposited on a Silica Glass Substrate

Inomata

Albrecht²,

Haruta

et al. 2019

Chem. Mater.

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Tin oxide quantum dots (QDs) have attracted much attention because of their low toxicity and the absence of cadmium and other poisonous elements. In this paper, we report the novel synthetic method for size-controlled tin oxide QDs using dendrimers as a template, and their electronic and structural properties. Hemispherical tin oxide QDs with a size below 2 nm and small size distribution were synthesized on silica glass substrates by the dendrimer-templated synthesis method (Sn 12 , Sn 28 , and Sn 60 oxide QDs). The structures of the tin oxide QDs were composed not only of Sn(IV) sites, but also Sn(II) sites due to the restriction of the coordination environment to stabilize the structure. Density functional theory calculation showed that a bare tin oxide cluster with a mixed valence state (Sn(II) + Sn(IV)) is more stable than those only with Sn(II) or Sn(IV). The synthesized tin oxide QDs showed the quantum confinement effect caused by the spatial confinement of an electron. The Urbach tail parameter, expressing the disorderliness of the QDs, decreased with the reduced QD size, although the value of each tin oxide QD was higher than that of bulk SnO 2 . The experimental band gap energy was compared with the effective mass approximation models, which are theoretical models for the quantum confinement effect. We found that the experimental values of Sn 28 and Sn 60 oxide QDs were consistent with the theoretical values, while Sn 12 oxide QDs had a lower value compared to the predicted band gap energy. This could be attributed to the change in the physical parameters of Sn 12 oxide QDs, which are not the same as those of Sn 28 , Sn 60 oxide QDs or the bulk SnO 2 . These results indicate that small tin oxide QDs have a different structure and different electronic properties compared to bulk or conventional nanoparticles and have potential applications in such fields as catalysis and optical and electronic devices.

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Section: Resultsmentioning

confidence: 99%

Dendrimer-Templated Synthesis and Characterization of Tin Oxide Quantum Dots Deposited on a Silica Glass Substrate

Inomata

Albrecht²,

Haruta

et al. 2019

Chem. Mater.

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“…Among these, quasi-zerodimensional systems (QD) became a hot topic, since the carrier motion is restricted to a narrow region of a few nanometers in dimension and its effects of hydrostatic pressure on QD were studied by many researchers. [10][11][12][13][14][15][16][17][18][19] Peter calculated the ionization energies in external perturbations such as hydrostatic pressure and magnetic field with a parabolic confinement for finite barrier quantum dots. [10] He found that the ionization energy is purely pressure dependent and for smaller dot sizes the hydrostatic pressure dominates.…”

Section: Introductionmentioning

confidence: 99%

“…[15] The effects of electric field, hydrostatic pressure, and temperature on the binding energy in SQD have been reported by Rezaei et al [16] Prodigious copies are available for the effects of hydrostatic pressure, temperature, and conduction band nonparabolicity on the impurity binding energy in an SQD. [17,18] Though the effects of hydrostatic pressure, temperature, and polaronic mass on the correlation energies in an SQD [19] have been widely investigated, very few reports explore the effect of polaron mass on donor binding and confined energies. Hence, the present work focuses on analyzing the hydrostatic pressure and polaronic effects in the SQD of the donor binding and confined energies.…”

Section: Introductionmentioning

confidence: 99%

Effect of hydrostatic pressure and polaronic mass of the binding energy in a spherical quantum dot

Jeice¹,

Jayam

Wilson³

2015

Chinese Phys. B

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Simultaneous effect of hydrostatic pressure and polaronic mass on the binding energies of the ground and excited states of an on-center hydrogenic impurity confined in a GaAs/GaAlAs spherical quantum dot are theoretically investigated by the variational method within the effective mass approximation. The binding energy is calculated as a function of dot radius and pressure. Our findings proved that the hydrostatic pressure led to the decrease of confined energy and the increase of donor binding energy. Conduction band non-parabolicity and the polaron masses are effective in the donor binding energy which is significant for narrow dots not in the confined energy. The maximum donor binding energy achieved by the polaronic mass in the ground and excited states are 2%–19% for the narrow dots. The confined and donor binding energies approach zero as the dot size approaches infinity.

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“…Many studies of the single-layered QD with a central donor impurity for different confining potential values, have been reported in [12,13,14,15,16]. Varshni in [17] calculated the energies for 1s, 2p and 3d states of a QD by using of the variational method.…”

Section: Introductionmentioning

confidence: 99%

Oscillator strengths of the intersubband electronic transitions in the multi-layered nano-antidots with hydrogenic impurity

Naimi

Jafari

2012

J Comput Electron

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In this study, we have obtained the exact solutions of the Schrödinger equation for a multi-layered quantum antidot (MLQAD) within the effective mass approximation and dielectric continuum model for the spherical symmetry. The MLQAD is nano-structured semiconductor system that consists of a spherical core (e.g. Ga 1−x Al x As) and a coated spherical shell (e.g. Ga 1−y Al y As) as the whole anti-dot is embedded inside a bulk material (e.g. GaAs). The dependence of the electron energy spectrum and its radial probability density on nano-system radius are studied. The numeric calculations and analysis of oscillator strength of intersubband quantum transition from the ground state into two first allowed excited states at the varying radius, for both the finite and infinite confining potential (CP) as well as constant shell thickness, are performed. It is shown that, in particular, the binding energy and the oscillator strength of the hydrogenic impurity of a MLQAD behave differently from that of a single-layered quantum antidot (SLQAD). For a MLQAD with finite core and shell CPs, the state energies and the oscillator strengths of the impurity are found to be dependent on the shell thickness. At the large core radius and very small shell thickness, our results are closer to respective values for a SLQAD that previously reported.

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Hydrostatic pressure and conduction band non-parabolicity effects on the impurity binding energy in a spherical quantum dot

Cited by 22 publications

References 19 publications

Dendrimer-Templated Synthesis and Characterization of Tin Oxide Quantum Dots Deposited on a Silica Glass Substrate

Dendrimer-Templated Synthesis and Characterization of Tin Oxide Quantum Dots Deposited on a Silica Glass Substrate

Effect of hydrostatic pressure and polaronic mass of the binding energy in a spherical quantum dot

Oscillator strengths of the intersubband electronic transitions in the multi-layered nano-antidots with hydrogenic impurity

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