CHARACTERIZATION OF OPTICALLY DENSE, DOPED SEMICONDUCTORS BY REFLECTION THZ TIME-DOMAIN SPECTROSCOPY

We present reflection THz-time domain spectroscopy measurements of the complex conductivity of Ir-type, 0.038 Omega cm GaAs and n-type, 0.22 Omega cm Si wafers. These measurements clearly demonstrate the effica cy of the reflection technique on highly conductive, optically dense s amples and approach the precision of TNz-TDS transmission measurements . Because the THz-bandwidth. reflection measurements extend beyond the carrier collision frequency, we obtain direct measures of the mobilit y and the carrier number density. (C) 1998 American Institute of Physi cs.