III-V compounds

Madelung, O.

doi:10.1007/978-3-642-18865-7_3

Cited by 20 publications

(16 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For all the materials considered here, the parameter α 48 Green squares denote results from experimental studies [4] (obscured by [5]) cyclotron resonance 25 [7] cyclotron resonance. 25 is inversely correlated with the band-gap of the material (Fig. 5).…”

Section: Sensitivity Of the Kane Dispersion Parameters To Electronmentioning

confidence: 98%

“…Our initial structures were determined as follows: The GaAs structure was taken from the Madelung handbook, 25 CdTe 26 and CZTS 27 (in the tetragonal phase) were taken from X-ray diffraction data, whilst MAPI was optimised starting from a pseudo-cubic (high temperature) structure available online. 28 For all atomic relaxations a quasi-Newtonian algorithm and the PBEsol exchange-correlation functional was used.…”

Section: A Electronic Band Structure Calculationsmentioning

confidence: 99%

See 1 more Smart Citation

Impact of nonparabolic electronic band structure on the optical and transport properties of photovoltaic materials

et al. 2019

View full text Add to dashboard Cite

The effective mass approximation (EMA) models the response to an external perturbation of an electron in a periodic potential as the response of a free electron with a renormalised mass. For semiconductors used in photovoltaic devices, the EMA allows calculation of important material properties from first-principles calculations, including optical properties (e.g. exciton binding energies), defect properties (e.g. donor and acceptor levels) and transport properties (e.g. polaron radii and carrier mobilities). The conduction and valence bands of semiconductors are commonly approximated as parabolic around their extrema, which gives a simple theoretical description, but ignores the complexity of real materials. In this work, we use density functional theory to assess the impact of band non-parabolicity on four common thin-film photovoltaic materials -GaAs, CdTe, Cu2ZnSnS4 and CH3NH3PbI3 -at temperatures and carrier densities relevant for real-world applications. First, we calculate the effective mass at the band edges. We compare finite-difference, unweighted least-squares and thermally weighted least-squares approaches. We find that the thermally weighted least-squares method reduces sensitivity to the choice of sampling density. Second, we employ a Kane quasi-linear dispersion to quantify the extent of non-parabolicity, and compare results from different electronic structure theories to consider the effect of spin-orbit coupling and electron exchange. Finally, we focus on the halide perovskite CH3NH3PbI3 as a model system to assess the impact of non-parabolicity on calculated electron transport and optical properties at high carrier concentrations. We find that at a concentration of 10 20 cm −3 the optical effective mass increases by a factor of two relative to the low carrier-concentration value, and the polaron mobility decreases by a factor of three. Our work suggests that similar adjustments should be made to the predicted optical and transport properties of other semiconductors with significant band non-parabolicity. arXiv:1811.02281v2 [cond-mat.mtrl-sci]

show abstract

Section: Sensitivity Of the Kane Dispersion Parameters To Electronmentioning

confidence: 98%

Section: A Electronic Band Structure Calculationsmentioning

confidence: 99%

Impact of nonparabolic electronic band structure on the optical and transport properties of photovoltaic materials

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The latter leads to splitting of the degenerate valence subbands, thus reducing the forbidden band width. In a general case, the 3D effect dominates usually, causing this width, E g , to increase in the In 0.25 Ga 0.75 As layer from about 1.18 eV [9,10] (T = 77 K) for nondeformed bulk material to 1.24 eV for a pseudomorphous elastically strained layer grown on a GaAs substrate [7]. The overall reduction of the forbidden band width through a change in the value of the elastic deformation of the layer came to about 0.06-0.08 eV.…”

mentioning

confidence: 97%

InGaAs/GaAs porous superlattice as new material for quantum electronics

Orlov

Ivina

Alyabina

et al. 2003

phys. stat. sol. (c)

View full text Add to dashboard Cite

We report on the first attempt to fabricate arrays of one-dimensional quantum wires from 2D layer In x Ga 1-x As/GaAs structures, based on a self-organization concept. A decrease in the dimensionality of the electron-hole gas in the objects of interest, which is due to a 2D to 1D electron subsystem transformation in the layers of this structure, is detected by the shift and narrowing of the PL spectral lines.Porous semiconductor materials that under electrochemical etching of a crystal provide a convenient medium for fabricating reduced dimensionality objects like two-dimensional planes [1, 2], quantum wires [3], and tunnel chains of quantum zero-dimensional grains [4,5] have recently become a subject of increasing interest. One way of creating a system of quantum wires is to fill the pores of a dielectric "host crystal" [3, 6] until a new chemical compound of a metal (Bi) or semiconductor (PbTe) type of conductivity is formed. In this work we discuss another approach to fabricate quantum wire arrays, which is based on the idea of their self-organization in the process of electrolytic etching of multilayer heteroepitaxial structures that contain nanometer-thick layers with a 2D electron-hole gas, built into these structures during the epitaxial growth. For the "host crystal" we used epitaxial single and multilayer, including periodic semiconductor heterostructures, i.e., GaAs/In x Ga 1-x As grown on GaAs (100) semi-insulating substrates, which were thoroughly studied elsewhere [7]. In x Ga 1-x As layers in the original samples formed single or double quantum wells; these layers were doped with a donor impurity from 10 15 to 10 16 cm -3. The total number N of quantum-size In x Ga 1-x As layers in the structures varied from 1 to 10. Brief information about the content (x) and the thickness of In x Ga 1-x As layers in quantum well structures (QWS) is presented in Table 1. Here d qw is the thickness of a single quantum well, d b is the thickness of the barrier in a double quantum well, x is the In content in the In x Ga 1-x As layer, d 1 = 2d qw + d b is the total thickness of a double quantum well. The double quantum wells were spaced in the GaAs crystal at about 0.07 µm [7].Our technique of forming 1D conductor arrays consisted in etching the oblique channels in a crystal, which intersect the planes of In x Ga 1-x As nanometer-thick layers built into the GaAs crystal. Electrochemical etching of samples was a standard operation performed in an alcoholic solution of hydrofluoric acid at the current densities of 20-40 mA/cm 2 under UV radiation. Etching of an In x Ga 1-x As/GaAs (100) structure is most likely to proceed along oblique channels in the (111) direction [1].

show abstract

“…where we define b = µ n /µ p and the hole parts are neglected because b ≈ 100 for InSb [10,11]. Equation (11) and Fig.…”

Section: A Carrier Concentrationmentioning

confidence: 99%

“…In the strong magnetic field limit, the Nernst coefficient of the intrinsic semiconductor becomes [10] N ≈ k |e|…”

Section: Mobility Of Holementioning

confidence: 99%

Transport coefficients of InSb in a strong magnetic field

Nakamura

Ikeda²,

Yamaguchi³

XVI ICT '97. Proceedings ICT'97. 16th International Conference on Thermoelectrics (Cat. No.97TH8291)

View full text Add to dashboard Cite

Improvement of a superconducting magnet system makes induction of a strong magnetic field easier. This fact gives us a possibility of energy conversion by the Nernst effect. As the first step to study the Nernst element, we measured the conductivity, the Hall coefficient, the thermoelectric power and the Nernst coefficient of the InSb, which is one of candidates of the Nernst elements. From this experiment, it is concluded that the Nernst coefficient is smaller than the theoretical values. On the other hand, the conductivity, the Hall coefficient ant the thermoelectric power has the values expected by the theory.

show abstract

III-V compounds

Cited by 20 publications

References 0 publications

Impact of nonparabolic electronic band structure on the optical and transport properties of photovoltaic materials

Impact of nonparabolic electronic band structure on the optical and transport properties of photovoltaic materials

InGaAs/GaAs porous superlattice as new material for quantum electronics

Transport coefficients of InSb in a strong magnetic field

Contact Info

Product

Resources

About