Mobility and carrier density in p-type GaAs nanowires measured by transmission Raman spectroscopy

Abstract

The unambiguous measurement of carrier concentration and mobility in semiconductor nanowires remains a challenging task. This is a consequence of their one-dimensional nature and the incompatibility with Hall or van der Pauw measurements. We propose a method that allows the direct determination of mobility and carrier concentration in nanowires in a contact-less manner. We demonstrate how forward Raman scattering enables the measurement of phonon–plasmon interactions. By applying this method to p-type GaAs nanowires, we were able to directly obtain values of the carrier concentration between 3.0 × 10¹⁷ and 7.4 × 10¹⁸ cm⁻³ and a mobility of 31 cm² (V s)⁻¹ at room temperature. This study opens the path towards the study of plasmon–phonon interactions in semiconductor nanowires.