Laser modulated IR transmission of semiconductors

Abstract
The influence of the charge carrier density on the IR properties of semiconductors is a well known effect, that can be exploited for the analysis of semiconductor materials. In this work, an experimental arrangement is presented, by which the IR transparency of thin semiconductor samples is modulated with the help of an Ar ion laser beam with photon energies h > E and by which the oscillating transmitted IR radiation of an external IR source is measured. The transmittance signal (amplitude and phase) which only depends on the charge carrier density can be used for the characterization of semiconductors independent of thermal parameters.