Abstract

Recently, Hu and Nuss [1] demonstrated an imaging system using terahertz transients generated by standard optoelectronic methods. We have used this system to measure spatial inhomogeneities in the doping density of epitaxial GaAs films. The absorption of THz radiation by doped semiconductors is a strong function of the conductivity, and as a result we are able to detect small variations in the level of doping with 250 µm spatial resolution. Such information is not easily obtainable by any other method, and this demonstration could lead to improved quality control in the growth of doped semiconductor wafers.

© 1996 Optical Society of America