Negative absolute mobility of holes in n-doped GaAs quantum wells

Abstract
We observe the effect of negative absolute mobility for minority holes in n‐modulation‐doped GaAs quantum wells at low temperatures. Photoinjected minority holes drift towards the positive electrode, which is shown experimentally using a photoluminescence imaging technique. The effect is attributed to ‘‘carrier drag’’ by the high‐mobility electron plasma via electron‐hole scattering. From a quantitative analysis we are able to determine electron‐hole momentum relaxation times.