Sökning: "oxygen doping"

Visar resultat 21 - 25 av 61 avhandlingar innehållade orden oxygen doping.

1. 21. MBE growth of Si-based heterostructures for optoelectronic applications

   Författare :Fabrice Duteil; Per-Olof Holtz; Linköpings universitet; []
   Nyckelord :;

   Sammanfattning : Molecular beam epitaxy (MBE) is a powerful technique used to grow semiconductor crystalline Jayers at low (200°C - 900 °C) temperature. In this study we report on the growth of silicon-based materials used for their electronic and optical properties. Parts of the work have involved alloys of silicon (Si) with germanium (Ge) or carbon (C). LÄS MER

3. 22. Photoelectrochemical Processes on Fe2O3 Based Model Anodes

   Författare :Beniamino Iandolo; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Near- field Enhancement; Hydrogen; Hematite; Water Splitting; Flatband Potential; Surface States.; Localized Plasmons; Nanoparticles;

   Sammanfattning : One possibility to partially satisfy the ever-increasing energy needs of modern society, without compromising the Earth’s environment through e.g. global warming, consists in harvesting solar energy and storing it as hydrogen produced from water splitting. This can potentially be achieved on a large scale using photoelectrochemical (PEC) cells. LÄS MER

4. 23. Solid state proton conductors: hydrated perovskites and hydrated alkali thio-hydroxogermanates

   Författare :Maths Karlsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; neutron scattering; vibrational spectroscopy; alkali thio-hydroxogermanates; Proton conductors; fuel cells.; perovskites;

   Sammanfattning : This thesis concerns experimental studies of hydrated perovskites and hydrated alkali thio-hydroxogermanates, two classes of solid state proton conductors which are promising to be used as electrolytes in future intermediate temperature (200-500°C) fuel cells.This is an attractive temperature range for many applications but for which today's available electrolytes do not show satisfactory performance. LÄS MER

5. 24. Structural and Electrical Transport Properties of Doped Nd-123 Superconductors

   Författare :Shaban Reza Ghorbani; KTH; []
   Nyckelord :high temperature superconductors; critical temperature; resistivity; thermoelectric power; Hall coefficient; X-ray diffraction; Neutron diffraction; NdBa2Cu3O7-delta; hole concentration; substitution;

   Sammanfattning : It is generally believed that one of the key parameterscontrolling the normal state and superconducting properties ofhigh temperature superconductors is the charge carrierconcentrationpin the CuO2planes.By changing the non-isovalent dopingconcentration on the RE site as well as the oxygen content in(RE)Ba2Cu3O7−δ, an excellent tool is obtained tovary the hole concentration over a wide range from theunderdoped up to the overdoped regime. LÄS MER

7. 25. Advanced Functional Materials for Intermediate-Temperature Ceramic Fuel Cells

   Författare :Zhan Gao; Bill Bergman; Mogens Mogensen; Ceramics; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Low to intermediate-temperature solid oxide fuel cell (SOFC, 500 oC-700 oC) based on doped ceria (DCO) electrolyte has attracted much attention during the last decade. However, DCO suffers from electronic conduction caused byreduction of Ce (IV) to Ce (III) at high temperatures and low oxygen partial pressures and has a high grain-boundary resistivity. LÄS MER