Optimisation of the Thermoelectric Figure of Merit of Modified Silicon Germanium Alloys
Abstract
In this report a working theoretical model for the power factor (alpha squared sigma) of silicon germanium alloys is presented and the dependence of this parameter on carrier concentration and number of valleys explored. Although silicon-germanium alloys cannot be described as narrow band gap semiconductors, the high level of doping employed in thermoelectric applications necessitates the inclusion in the theoretical model of deviations from the usually assumed parabolic bands. The dependence of the Seebeck coefficient (alpha), electrical conductivity (sigma) and the power factor (alpha squared sigma) on carrier concentration and number of valleys N sub v are presented. Two main conclusions can be drawn from the reported results. A large number of equi-energetic valleys give rise to a higher power factor at room temperature, when intervalley scattering can be considered negligibly small. Higher doping levels are required in order to take advantage of the large number of valleys. Keywords: Semiconductors.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1988
- Accession Number
- ADA196673
Entities
People
- D. M. Rowe
Organizations
- University of Wales