Landau–Ginzburg–Devonshire Theory for Domain Wall Conduction and Observation of Microwave Conduction of Domain Walls

This chapter concerns DW electrical conduction. It first addresses the phenomenology of charged domain walls in the context of a Landau-Ginzburg-Devonshire (LGD) model for the ferroelectric semiconductor with analysis of the DW conductivity associated with accumulation of charge carriers near domain walls. It is revealed that there exists an interplay between the wall type — head-to-head or tail-to-tail — and conduction type of the semiconductor ferroelectric with a strong dependence of the domain wall conductivity on the wall orientation. The chapter then reviews observations of high-frequency — in the gigahertz frequency range — ac conductivity along the nominally uncharged 180-degree domain walls in a uniaxial Pb(Zr0.2Ti0.8)O3 epitaxial film. Measurements of the conduction at high frequencies are insensitive to presence of a Schottky barrier and the electrode-ferroelectric interface.

Optimization and modulation for the moderate and high temperature thermoelectric properties of PbSe via solid solution with PbS synthesized by HPHT

PbS synthesized at the same condition with PbSe exhibits an opposite electrical conduction type from it. Via the solid solution of PbS into PbSe, we attempt to change the major carries kind of PbSe-base materials and improve the thermoelectric (TE) property of synthesis samples in corresponding temperature areas. Introduction of high pressure into the synthesis stage could reduce the reactive activation energy and improve the synthesis efficiency. Characterizations via the electron microscopes demonstrate that synthesis samples are made of multiscale grains. Finally, characterizations on the thermoelectrical properties of [Formula: see text] demonstrate that the solid solution treatment could modulate the electrical conduction type and the figure of merit effectively.

Temperature-driven n–p conduction type switching without structural transition in a Cu-rich chalcogenide, NaCu5S3

We report for the first time the discovery of reversible n–p conduction type switching in a chalcogenide, NaCu5S3, without structural transition.

SPECIAL MECHANISM OF CONDUCTION TYPE INVERSION IN PLASTICALLY DEFORMED n-Si

The aim of research is studying the mechanism of n–p inversion of the conduction type of deformed silicon crystals in the course of their thermal treatment. Initially, almost non-dislocation zone-melted phosphorus-doped n-Si single crystals with electron concentration of 2×1014 cm–3 were studied. Uniaxial compression at temperature of 700 °С and pressure of 25 MPa increased the dislocation density to 108 cm–2. After long (within 30 min) cooling of the deformed crystals to room temperature, an n–p inversion of the conduction type occurred. The effect is explained by the formation of phosphorus–divacancy complexes PV2 in the defective atmosphere of dislocations, which are acceptor centers with energy level of Ev+0.34 eV. The found out n–p inversion mechanism differs from the standard one for plastically deformed n-type semiconductors with a diamond-like crystalline structure, which consists in the formation of acceptor centers along edge dislocations.