Optical properties of degenerately doped silicon films for applications in thermophotovoltaic systems

The dependence of the plasma wavelength and free-carrier absorption on the doping concentration in silicon was investigated. Two methods of introducing impurities into Si were utilized to attain high doping concentration. One was the diffusion method employing spin-on dopants. The other technique was doping by ion implantation followed by thermal annealing with a capped layer of doped glass. The high temperature annealing which was needed to activate the dopant atoms and to repair the implantation damage also produced significant redistribution of the dopants.