Probing the momentum relaxation time of charge carriers in ultrathin semiconductor layers

TL;DR

This paper introduces a terahertz time-domain method to directly measure the momentum relaxation time of charge carriers in ultrathin semiconductor layers, providing a new tool for characterizing novel materials.

Contribution

The paper presents a phase-sensitive terahertz technique that directly measures carrier relaxation times, aligning with electrical data and applicable to unknown material parameters.

Findings

Accurate measurement of relaxation times in ultrathin layers.

Agreement between terahertz and electrical characterization.

Method applicable to novel materials with unknown parameters.

Abstract

We report on a terahertz time-domain technique for measuring the momentum relaxation time of charge carriers in ultrathin semiconductor layers. The phase sensitive modulation technique directly provides the relaxation time. Time-resolved THz experiments were performed on n-doped GaAs and show precise agreement with data obtained by electrical characterization. The technique is well suited for studying novel materials where parameters such as the charge carriers' effective mass or the carrier density are not known a priori.