Electrical properties of lead telluride single crystals doped with Gd
Temperature dependences of electric conductivity, free carrier concentration and mobility in single-crystalline PbTe: Gd samples with a varied impurity content are investigated. The features of electron transport in PbTe: Gd may be caused by a variable gadolinium valence. The striking result from the Seebeck coefficient measurements is that the thermoelectric power factor increases dramatically. Measurements of the magnetic susceptibility at low temperatures permit us to suggest that Gd ions exist in different charge states.
2D layered black arsenic-phosphorus materials: Synthesis, properties, and device applications
Phosphorene, especially black phosphorus (BP), has attracted considerable attention due to the unique characteristics, such as tunable direct bandgap, high carrier mobility, and strong in-plane anisotropy. Recently, a new modification strategy for black phosphorus has been developed by alloying black phosphorus with the congener element arsenic. The elemental composition tuning of black phosphorus with arsenic can not only maintain its special crystal structure and high anisotropy but also modify its electrical and optical properties for the further applications of multifunctional devices. The achieved two-dimensional (2D) black arsenic-phosphorus materials exhibit outstanding optical, electrical, and photoelectric properties, such as very narrow band gap, anisotropic infrared absorption, and bipolar transfer characteristics, presenting great potential in infrared photodetectors and high-performance field effect transistors (FETs). In this review, we introduce the recent progress made in the synthesis and applications of black arsenic-phosphorus, and provide an outlook and perspectives on the current challenges and future opportunities in this field. We hope that this review can bring new insights and inspirations on the further development of 2D black arsenic-phosphorus based materials and devices.
Deep level defects in narrow gap semiconductors
Mise au point. Methodes experimentales. Modeles theoriques des defauts a niveaux profonds dans les semiconducteurs a bande interdite etroite de type IV-VI et II-VI