Investigation and Simulation of the Optical Properties of Doped Silicon

Abstract

This work summarizes studies in a project work of the optical properties of electrical grade poly crystalline doped silicon (Si) wafers for industrial solar cells. The focus was set on varying high doping rates of phosphorus for the reverse side contact and aluminium as a back surface reflector of the solar cell. The work also included the calculation of the degree of ionization at room temperature using the numerically solved neutrality condition involving the Fermi integrals. The optimization of the light confining geometry in the near infrared wavelength range was done by use of a ray tracing simulation program and analytical calculation of the solutions for reflectance R and transmittance T concerning single , double and n layer antireflection coatings. For the latter the matrix method has been used. The optical loss from excessive doping at the backside for a back surface field has been quantified and studied. It has been shown that the doping is not a limit for charge carrier generation below and in the range of the band edge.