Crystalline compounds built up of periodically ordered nanostructured inorganic semiconductor motifs and organic molecules are a new type of hybrid semiconducting materials that are of great fundamental importance and technological relevance. [1][2][3][4][5][6][7][8][9] The most appealing feature of these materials is that many favorable properties of each individual component are brought into the hybrid structure by incorporating two distinctly different components into a single crystal lattice. Integration and combination of exceptional transport properties and structural/thermal stability from the inorganic component and superb flexibility and processibility from the organic component can be expected. Additionally, the blending of the inorganic and organic modules in these crystalline hybrid structures takes place at the atomic level and through chemical bonds, and thus is free of the interface issues that are inevitably present in conventional hybrid composite materials. Furthermore, the formation of such hybrid crystals almost always leads to unique and remarkable new features that are not possible for the individual constituents. Some notable examples include organic-inorganic perovskite-like structures and related materials, [1][2][3][4] hybrid metal oxides, [5,6] and semiconductors composed of zinc blende and wurtzite frameworks. [7][8][9] The II/VI based hybrid semiconductor crystal structures (II: Group 12 elements and Mn; VI: Group 16 elements) are composed of one-dimensional (1D) chains or two-dimensional (2D) slabs of II/VI semiconductor fragments that are interconnected or separated by organic amine molecules to form periodic crystal lattices. They are of the general formula [MQ(L) x ] (M = Mn, Zn, Cd; Q = S, Se, Te; L = organic amine or diamine; and x = 0.5, 1). The most intriguing observations include extremely strong band-edge absorption (e.g. 10-20 times higher than bulk II/VI and GaAs) and exceedingly large band-gap tunability (0.1-2.0 eV) as a result of very strong structure-induced quantum confinement. [10][11][12] Although, according to theoretical calculations, [10] the organic spacers give rise to a very limited effect on the band-gap-related electronic and optical properties, they play a crucial role in the structural, mechanical, and thermal behaviors of these hybrid materials. Herein, we report five crystal structures of 3D-[ZnTe(L) 0.5 ] made of ZnTe single-atomic slabs and longchain diamines, as well as their structural phase transitions, mechanical properties, specific heat capacity, thermal diffusivity, and thermal conductivity. Our analysis shows that crystalline hybrid semiconductors of this type are much lighter and substantially more flexible than their inorganic counterparts. The incorporation of organic molecules into the semiconductor crystal lattices also leads to significantly reduced thermal conductivity that is most desirable for high performance thermoelectric materials with structural integrity. [13][14][15] All the compounds were synthesized by solvothermal reactions u...

Galvanomagnetic and thermomagnetic data of single crystal indium rich Pb1−xSnxTe are analyzed, and electronic band parameters are calculated using nonparabolic band model. Transport properties at 80K are presented as a function of Sn (x=0–0.3) and In concentrations. Our results indicate pinning of Fermi level by indium impurity levels in these alloys. Effects of interaction of band with impurity level are investigated in terms of change in effective mass and energy scattering exponent. Indium doping slightly improves the thermoelectric properties of PbSnTe alloys.

MO3 (M = Mo, W) or VI-VI binary compounds are important semiconducting oxides that show great promise for a variety of applications. In an effort to tune and enhance their properties in a systematic manner we have applied a designing strategy to deliberately introduce organic linker molecules in these perovskite-like crystal lattices. This approach has led to a wealth of new hybrid structures built on one-dimensional (1D) and two-dimensional (2D) VI-VI modules. The hybrid semiconductors exhibit a number of greatly improved properties and new functionality, including broad band gap tunability, negative thermal expansion, largely reduced thermal conductivity, and significantly enhanced dielectric constant compared to their MO3 parent phases.

A low band gap iron sulfide hybrid semiconductor with unique layered structure and unusual iron coordination exhibits significantly reduced thermal conductivity.

Polycrystalline alloys of PbSe with rare-earth elements (Ce, Pr, Nd, Eu, Gd, and Yb) have been prepared and their magnetic susceptibility (from 4 to 120 K), galvanomagnetic and thermomagnetic transport (from 80 to 380 K) properties have been measured. Most samples are paramagnetic, and the concentration of rare-earth atoms in the PbSe lattice is deduced from fitting a Curie-Weiss law. The electrical conductivity, Hall, Seebeck, and transverse Nernst-Ettingshausen effects are interpreted in terms of the carrier density and mobility, the density of states effective mass, and the scattering exponent. In summary, Pb1−xEuxSe is a semiconductor with a wider gap than PbSe, but the carrier density is unaffected by the presence of Eu. The other rare earths, which are essentially trivalent atoms, act as donors, with a doping efficiency close to unity in the case of Ce and Nd, but much less for Gd and Yb. The mechanisms that govern the observed decrease in mobility are also discussed.