Photo-luminescence studies of hot electrons and real space transfer effect in a double quantum well superlattice

Abstract

A GaAsAlGaAs superlattice of which unit cell has two GaAs quantum wells shows a negative differential resistance under electric fields applied parallel to the superlattice plane at E ≳ 1 kV/cm (300 K) or at E ≳ 0.5 kV/cm (77 K). The photo-luminescence at 77 K shows a dominant peak I A followed by a small peak I B. Under the electric field the high energy tail of the dominant peak is enhanced and the intensity of the second peak I B is increased, which confirms the occurence of the real space transfer of hot electrons from the wide quantum well to the narrow one.