Сканирующая туннельная микроскопия в халькогенидных термоэлектриках (Bi, Sb)-=SUB=-2-=/SUB=-(Te, Se, S)-=SUB=-3-=/SUB=-

The morphology studies of the interlayer surface (0001) were carried out by the method of scanning tunneling microscopy in the n–Bi1.6Sb0.4Te2.94Se0.06, n- Bi1.8Sb0.2Te2.82Se0.09S0.09, p-Bi0.8Sb1.2Te2.91Se0.09 and p-Bi0.7Sb1.3Te2.91Se0.09 solid solutions. On the surface (0001), impurity and native defects were found (vacancies of tellurium, antisite defects, adatoms), formed in the compositions due to substitutions of atoms in the Bi2Te3 sublattices. The average values of HM and the standard deviations of HS in height in the distribution of atoms on the surface are determined depending on the composition of the solid solution. The effect of detected defects on the thermoelectric properties of solid solutions has been established.

Deep level transient spectroscopy and photoluminescence studies of hole and electron traps in ZnSnP2 bulk crystals

ZnSnP2, an emerging inorganic material for solar cells, was characterized by deep level transient spectroscopy (DLTS) and photoluminescence (PL). Acceptor- and donor-like traps with shallow energy levels were detected by DLTS analysis. The previous study based on first-principle calculation also suggested such traps were due to antisite defects of Zn and Sn. PL measurements also revealed sub-gap transitions related to these trap levels. Additionally, DLTS found a trap with deep level in ZnSnP2. A short lifetime of minority carrier in previous work might be due to such trap, coming from phosphorus vacancies and/or zinc interstitials suggested by first-principle study.

Molecular dynamics study on single particle displacement damage of ZB InN

To evaluate single-particle initial displacement damage of InN, the MD method is used to simulate the cascades, where the energy of PKA (E PKA) ranges from 1 to 5 keV. From these results, we can find that high EPKA will increase Np and Ns of defects, and aggravate the damage of InN, which is more obvious in Frenkel pairs. The formation efficiency of vacancy and interstitial is influenced by antisite defects, thereby causing the difference between vacancies and interstitials for the same atomic type. About the distribution of InN defects, it is mainly caused by vacancy defects, indicating that vacancy damage occupies the main position in displacement damage.

Crystal Structure Defects and Imperfections

Alloying, heat treating, and work hardening are widely used to control material properties, and though they take different approaches, they all focus on imperfections of one type or other. This chapter provides readers with essential background on these material imperfections and their relevance in design and manufacturing. It begins with a review of compositional impurities, the physical arrangement of atoms in solid solution, and the factors that determine maximum solubility. It then describes different types of structural imperfections, including point, line, and planar defects, and how they respond to applied stresses and strains. The chapter makes extensive use of graphics to illustrate crystal lattice structures and related concepts such as vacancies and interstitial sites, ion migration, volume expansion, antisite defects, edge and screw dislocations, slip planes, twinning planes, and dislocation passage through precipitates. It also points out important structure-property correlations.

An antisite defect mechanism for room temperature ferroelectricity in orthoferrites

Single-phase multiferroic materials that allow the coexistence of ferroelectric and magnetic ordering above room temperature are highly desirable, motivating an ongoing search for mechanisms for unconventional ferroelectricity in magnetic oxides. Here, we report an antisite defect mechanism for room temperature ferroelectricity in epitaxial thin films of yttrium orthoferrite, YFeO3, a perovskite-structured canted antiferromagnet. A combination of piezoresponse force microscopy, atomically resolved elemental mapping with aberration corrected scanning transmission electron microscopy and density functional theory calculations reveals that the presence of YFe antisite defects facilitates a non-centrosymmetric distortion promoting ferroelectricity. This mechanism is predicted to work analogously for other rare earth orthoferrites, with a dependence of the polarization on the radius of the rare earth cation. Our work uncovers the distinctive role of antisite defects in providing a mechanism for ferroelectricity in a range of magnetic orthoferrites and further augments the functionality of this family of complex oxides for multiferroic applications.