Interface roughness scattering in thin quantum wells

Abstract

Electronic transport coefficients of very thin undoped GaInP/GaAs quantum wells have been measured at low temperatures by the low field Hall effect and by the Shubnikov-de Haas effect. Unlike the case in undoped AlGaAs/GaAs, strong Shubnikov-de Haas oscillations were observed in this structure after increasing the carrier concentration via the persistent photoconductivity effect. Low temperature mobilities close to 70 000 cm2 V-1 s-1 at a carrier concentration of 6.5 × 1011 cm-2 were observed in a 25 Å quantum well. The results are compared with the theory of interace roughness scattering and we find that the mobility of our samples goes as L1.3 where L is the well width. We conclude that the barrier height of the confining potential plays a very important role in determining the effect of interface roughness scattering on the mobility of very thin quantum wells.