Conduction band intersubband transitions in Ge/SiGe quantum wells

Abstract

In this letter we present the experimental evidence of intersubbandabsorption in the conduction band of compressively strained germaniumquantum wells bounded by Ge-rich SiGe barriers. The measured absorptionenergies are in the terahertz range and are interpreted by means oftight binding calculations which include self-consistent band-bendingand depolarization effects. From the comparison of experimental andnumerical results a conduction band offset along the L line of about120 meV has been estimated for the studied heterostructures.