Study of surface electric field and photocarrier dynamics in InAs by means of a modified double-pump-pulse terahertz emission method

Abstract

In this study we report the investigation of terahertz (THz) emission efficiency dynamics in p-type InAs using a double-pump-pulse (DPP) THz emission method. We also suggest a novel modification of the standard DPP method which allows us to measure the indirectly modulated THz pulse. The obtained results reveal that the first optical pulse increases the free carrier concentration and enhances the surface electric field. This field prevents perpendicular but improves parallel to the surface electric dipole formation after sample excitation with the second optical pulse. Our suggested method is shown to be a more precise and sensitive way to study electric fields and photocarrier dynamics in semiconductors after photoexcitation.