Electrical Transport Properties from Long Wavelength Ellipsometry

Electrical transport properties (resistivity, scattering time, carrier concentration, mobility, effective mass) can be deduced from the Drude model for free carrier optical absorption. Optical response of materials may include simultaneous contributions from free carriers, phonon modes, and electronic transitions, however. Improved sensitivity to free carrier absorption and electrical transport properties is obtained through the use of long wavelength extended spectroscopic ellipsometry in the infrared (IR) and millimeter (THz) ranges. Non-contacting optical measurement and analysis methodologies are designed for semiconductors and transparent conductors used in photovoltaics (PV). Case studies include ZnO:Al, InP, wafer Si, and slnale crystal CdTe.