Multiband tight-binding theory of disordered ABC semiconductor quantum dots: Application to the optical properties of alloyed CdZnSe nanocrystals

Abstract

Zero-dimensional nanocrystals, as obtained by chemical synthesis, offer a broad range of applications, as their spectrum and thus their excitation gap can be tailored by variation of their size. Additionally, nanocrystals of the type ABC can be realized by alloying of two pure compound semiconductor materials AC and BC, which allows for a continuous tuning of their absorption and emission spectrum with the concentration x. We use the single-particle energies and wave functions calculated from a multiband sp^3 empirical tight-binding model in combination with the configuration interaction scheme to calculate the optical properties of CdZnSe nanocrystals with a spherical shape. In contrast to common mean-field approaches like the virtual crystal approximation (VCA), we treat the disorder on a microscopic level by taking into account a finite number of realizations for each size and concentration. We then compare the results for the optical properties with recent experimental data and calculate the optical bowing coefficient for further sizes.

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Cited by in corpus (4)

• Determination of the valence band offset at cubic CdSe/ZnTe type II heterojunctions: A combined experimental and theoretical approach
• Theory of band gap bowing of disordered substitutional II-VI and III-V semiconductor alloys
• Ground state spin and excitation energies in half-filled Lieb lattices
• Structure-Related Optical Fingerprints in the Absorption Spectra of Colloidal Quantum Dots: Random Alloy vs. Core/Shell Systems