Energy-band structure of CdTe and Si: a sp3(s∗)2 k.p model

Boujdaria, K.; Zitouni, Omar

doi:10.1016/j.ssc.2003.07.011

Cited by 16 publications

(10 citation statements)

References 9 publications

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“…For the computation of the photoresponse (discussed below), we use a modified 2x2 scheme (or two subband model). Originally k • p was done for the direct bandgap materials, although usage of it has been extended to indirect bandgap materials (Si and Ge) [20][21][22][23][24][25] , and one can adapt the present method to originally indirect bulk materials.…”

Section: A Hamiltonianmentioning

confidence: 99%

Optoelectronic response calculations in the framework of k·p coupled to non-equilibrium Green's functions for one-dimensional systems in the ballistic limit

Buin

Verma

Saini

2013

Journal of Applied Physics

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We present theory of the carrier-optical interaction in 1D systems based on the nonequilibrium Greens function formalism in the 4x4 k · p model. As a representative parameters we chose the GaAs. Although theory is presented in 4x4kp many subbands, results and discussion section is based on the simplified model such as 2x2 kp model (two transverse modes). Even though 2x2 kp model is simple enough it shows many phenomena that have not been seen before. We focus mainly on the ballistic extraction of photogenerated free carriers at the radiative limit which is described by the self-energy term derived in dipole approximation and solved in self-consistent manner with Keldysh quantum kinetic equations. Any relaxation or non-radiative recombination mechanisms as well as excitonic features are neglected.Effect of non-locality of electron-photon self energy term is considered and discussed.Spontaneous emission is also considered and shown to be small in short devices under medium bias conditions. Electron and hole spatial current oscillations are seen and discussed. It is shown that neglecting off-diagonal correlation in the band index not only produces quantitatively wrong results but it also alters the qualitative picture.All simulations are done in the full-rank approximation , with all spatial and band correlation effects are kept intact. This allows us to study not only quantitative effects but also qualitative behaviour.

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Section: A Hamiltonianmentioning

confidence: 99%

Optoelectronic response calculations in the framework of k·p coupled to non-equilibrium Green's functions for one-dimensional systems in the ballistic limit

Buin

Verma

Saini

2013

Journal of Applied Physics

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“…For CdTe we take the following parameter values at T = 0: E P0 = 21.07 eV, E P1 = 5.1 eV, E Q = 13.29 eV (see Ref. 30), E 0 = -1.6 eV 31 , ∆ 0 = -0.95 eV 32,33 , E 1 = 3.76 eV 34,35 , ∆ 1 = 0.27 eV 30 , ∆ = -0.19 eV 30 , C = -0.5355 and C ′ =-0.0129. The far-band contributions are taken to obtain at T = 0 the band edge values m * 0 = 0.093 m 0 36 and g * 0 = -1.66 9 .…”

Section: Cdtementioning

confidence: 99%

Temperature dependence of the electron spin g factor in CdTe and InP

Pfeffer

Zawadzki

2012

Journal of Applied Physics

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Temperature dependence of the electron spin g factors in bulk CdTe and InP are calculated and compared with experiment. It is assumed that the only modification of the band structure related to temperature is a dilatation change in the fundamental energy gap. The dilatation changes of fundamental gaps are calculated for both materials using available experimental data. Computations of the band structures in the presence of a magnetic field are carried out employing five-level P·p model appropriate for medium-gap semiconductors. In particular, the model takes into account spin splitting due to bulk inversion asymmetry (BIA) of the materials. The resulting theoretical effective masses and g factors increase with electron energy due to band nonparabolicity. Average g values are calculated summing over populated Landau and spin levels properly accounting for the thermal distribution of electrons in the band. It is shown that the spin splitting due to BIA in the presence of magnetic field gives observable contributions to g values. Our calculations are in good agreement with experiment in the temperature range of 0 K to 300 K for CdTe and 0 K to 180 K for InP. The temperature dependence of g is stronger in CdTe than in InP due to different signs of the bandedge g values in the two materials. Good agreement between the theory and experiment strongly indicates that the temperature dependence of spin g factors is correctly explained. In addition, we discuss formulas for the energy dependence of spin g factor due to band nonparabolicity, which are liable to misinterpretation.

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“…Thanks to the expansion of nanoscience over the years, semiconductor nanocrystals, also called quantum dots (QDs), gathered momentum and proved unavoidable in FRET based biosensors . These nanoparticles exhibit unique electronic and optical properties arising from their nanoscale dimensions which entail quantum confinement effects. QDs band gap energy is therefore size‐dependent, driving to tunable emission spectra .…”

Section: Introductionmentioning

confidence: 99%

How Quantum Dots Aggregation Enhances Förster Resonant Energy Transfer

et al. 2020

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As luminescent quantum dots (QDs) are known to aggregate themselves through their chemical activation by carbodiimide chemistry and their functionalization with biotin molecules, we investigate both effects on the fluorescence properties of CdTe QDs and their impact on Förster Resonant Energy Transfer (FRET) occurring with fluorescent streptavidin molecules (FA). First, the QDs fluorescence spectrum undergoes significant changes during the activation step which are explained thanks to an original analytical model based on QDs intra-aggregate screening and inter-QDs FRET. We also highlight the strong influence of biotin in solution on FRET efficiency, and define the experimental conditions maximizing the FRET. Finally, a free-QD-based system and an aggregated-QD-based system are studied in order to compare their detection threshold. The results show a minimum concentration limit of 80 nM in FA for the former while it is equal to 5 nM for the latter, favouring monitored aggregation in the design of QDs-based biosensors.

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Energy-band structure of CdTe and Si: a sp3(s∗)2 k.p model

Cited by 16 publications

References 9 publications

Optoelectronic response calculations in the framework of k·p coupled to non-equilibrium Green's functions for one-dimensional systems in the ballistic limit

Optoelectronic response calculations in the framework of k·p coupled to non-equilibrium Green's functions for one-dimensional systems in the ballistic limit

Temperature dependence of the electron spin g factor in CdTe and InP

How Quantum Dots Aggregation Enhances Förster Resonant Energy Transfer

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