Tight-Binding model for semiconductor nanostructures

Abstract

An empirical $s_c{p}_a^3$ tight-binding (TB) model is applied to the investigation of electronic states in semiconductor quantum dots. A basis set of three $p$-orbitals at the anions and one $s$-orbital at the cations is chosen. Matrix elements up to the second nearest neighbors and the spin-orbit coupling are included in our TB-model. The parametrization is chosen so that the effective masses, the spin-orbit-splitting and the gap energy of the bulk CdSe and ZnSe are reproduced. Within this reduced $s_c{p}_a^3$ TB-basis the valence (p-) bands are excellently reproduced and the conduction (s-) band is well reproduced close to the $\Gamma$-point, i.e. near to the band gap. In terms of this model much larger systems can be described than within a (more realistic) $s{p}^3{s}^{\ast }$-basis. The quantum dot is modelled by using the (bulk) TB-parameters for the particular material at those sites occupied by atoms of this material. Within this TB-model we study pyramidal-shaped CdSe quantum dots embedded in a ZnSe matrix and free spherical CdSe quantum dots (nanocrystals). Strain-effects are included by using an appropriate model strain field. Within the TB-model, the strain-effects can be artifically switched off to investigate the infuence of strain on the bound electronic states and, in particular, their spatial orientation. The theoretical results for spherical nanocrystals are compared with data from tunneling spectroscopy and optical experiments. Furthermore the influence of the spin-orbit coupling is investigated.

References in corpus (12)

• Electron transport through double quantum dots
• Eight-band calculations of strained InAs/GaAs quantum dots compared with one, four, and six-band approximations
• Theoretical interpretation of the experimental electronic structure of lens shaped, self-assembled InAs/GaAs quantum dots
• Evolution of the electronic structure with size in II-VI semiconductor nanocrystals
• Excitonic properties of strained wurtzite and zinc-blende GaN/Al(x)Ga(1-x)N quantum dots
• Electron-hole correlations in semiconductor quantum dots with tight-binding wave functions
• Polarons in semiconductor quantum-dots and their role in the quantum kinetics of carrier relaxation
• Realistic Tight Binding Model for the Electronic Structure of II-VI Semiconductors
• Tight-binding study of the influence of the strain on the electronic properties of InAs/GaAs quantum dots
• Effect of wetting layers on the strain and electronic structure of InAs self-assembled quantum dots
• Coulomb effects in semiconductor quantum dots
• Tight-binding g-Factor Calculations of CdSe Nanostructures

Cited by in corpus (12)

• A comparison of atomistic and continuum theoretical approaches to determine electronic properties of GaN/AlN quantum dots
• Influence of symmetry and Coulomb-correlation effects on the optical properties of nitride quantum dots
• Optical properties of self-organized wurtzite InN/GaN quantum dots: A combined atomistic tight-binding and full configuration interaction calculation
• Determination of the valence band offset at cubic CdSe/ZnTe type II heterojunctions: A combined experimental and theoretical approach
• Tutorial: Exciton resonances for atomically-thin optics
• Coulomb scattering in nitride based self-assembled quantum-dot systems
• Band gap bowing of binary alloys: Experimental results compared to theoretical tight-binding supercell calculations for CdZnSe
• Theory of band gap bowing of disordered substitutional II-VI and III-V semiconductor alloys
• Quantum-Confined Stark Effect in polar and nonpolar Wurtzite InN/GaN Heterostructures: Influence on Electronic Structure and Compensation by Coulomb Attraction
• Multiband tight-binding theory of disordered ABC semiconductor quantum dots: Application to the optical properties of alloyed CdZnSe nanocrystals
• Multiband effective bond-orbital model for nitride semiconductors with wurtzite structure
• Construction of optimized tight-binding models using \textit{ab initio} Hamiltonian: Application to monolayer $2H$-transition metal dichalcogenides