Investigation of the Field‐Dependent Carrier Mobility in GaAs by Picosecond Photoconductivity Measurements

Abstract

The carrier velocity is measured in Cr-compensated GaAs in dependence on the applied field strength by picosecond photoconductivity measurements. Two different behaviours are obtained in dependence on the excitation energy. In the case of low excitation a region of negative differential conductivity due to the electron transfer from r-valley into the L-valley exists. I n the case of high excitation the formation of charge domains lowers the mobility.Die Elektronendriftgeschwindigkeit in a-kompensiertem GaAs wird mittels PikosekundenPhotoleitfahigkeit bei unterschiedlichen Feldstiirken nnterwcht. Die gemessene Abhiingigkeit unteracheidet aich bei ~terschiedlichen Anregnngsenergien. h i niedriger Anregung wird ein Gebiet negativer differentieller Leitfiihigkeit gefunden, was sich auf den Elektronentransfer vom I'-Punkt zum L-Punkt des Leitungsbandes zuriickfiihren la&. Bei hoher Anregung verringert das Auftreten von Ladungsdomiinen die Beweglichkeit.

Nonlinear terahertz metamaterial perfect absorbers using GaAs [Invited]

“…Besides the carrier density increase, IVS is induced by the enhanced THz electric field [19]. Electrons that are accelerated to an energy of ∼1 eV can scatter from the Γ valley to the L valley [34]. The electrons in the Γ valley have a mobility of 4200 cm −2 • s −1 V −1 , while those in the L valley have a mobility of 400 cm −2 • s −1 V −1 .…”