XXIV Международный симпозиум Нанофизика и наноэлектроника", Нижний Новгород, 10-13 марта 2020 г. Анализ фононных мод и электрон-фононного взаимодействия в квантово-каскадных лазерных гетероструктурах

The phonon modes of quantum cascade heterostructures based on binary and ternary semiconductor compounds are modeled. The dependences of the frequencies of the interface phonon modes of the structure on the wave vector in the plane of the layers and on the phase shift in the period of the superlattice are calculated. It was found that the range of variation of the quantum energy of the phonon modes of the GaAs/Al0.25Ga0.75As structure does not exceed 2 meV. The calculated resulting interband scattering rate in the structure, taking into account the interface and confined modes, practically does not differ from the calculations in the approximation of bulk phonons of the structure.

Novel photocatalytic water splitting solar-to-hydrogen energy conversion: CdLa2S4 and CdLa2Se4 ternary semiconductor compounds

Comprehensive ab initio calculations from first- to second-principles methods are performed to investigate the suitability of non-centro-symmetric CdLa2S4 and CdLa2Se4 to be used as active photocatalysts under visible light illumination.

A Model for Estimating Chemical Potentials in Ternary Semiconductor Compounds: the Case of InGaAs

ABSTRACTIn ab initio modeling of doped semiconductors, estimation of defect formation energies involving substitutional sites of ternary compounds is ambiguous due to an approximate treatment of chemical potential of the substituted atoms. We propose a model of assigning fractions of the formation energy to individual atoms of a ternary semiconductor and test it on InGaAs. The accuracy of this approximation is on the order of 0.1 eV/atom and is expected to be sufficient for many practical purposes.

Ordering in Compound Semiconductors: The Role of Transmission Electron Microscopy

In this paper, the ordering of ternary semiconductor compounds is briefly reviewed by means of a coordination polyhedron model. Long-range ordering of chalcopyrite and CuAu-type structures can be represented as an array of repeating A2B2 tetrahedra. A CuAu-type ordered phase in a chalcopyrite AIBIIICVI2 compound is surrounded by an A3B+ AB3 boundary, whereas a CuPt-type ordered phase in a zinc-blende (A, B)IIICV compound is surrounded mainly by A2B2 type tetrahedra and thus restricted in size. Following the description of the ordered structure model, the detection of the asymmetry in ordering directions in (A, B)IIICV compounds is discussed. Some examples that employ transmission electron microscopy are presented.