INPLANE EFFECTIVE MASSES AND QUANTUM SCATTERING TIMES OF ELECTRONS IN NARROW MODULATION-DOPED INGAAS/INP QUANTUM-WELLS

In-plane effective masses m(parallel-to)* and quantum scattering times are derived from temperature-dependent Shubnikov-de Haas oscillations measured on a series of modulation-doped InxGa1-xAs/InP quantum wells with x=0.53 and 0.75, and for well widths ranging from 3 to 7 nm. The values for m(parallel-to)* are consistently higher by 30%-70% than the respective bulk data. This result is in good agreement with recent theoretical calculations which predict an increase of m(parallel-to)* with decreasing well width. The scatter of the mass values for nominally identical quantum wells is assumed to reflect corresponding variations of the well widths. The ratio of quantum to classical scattering times and the carrier density dependence of the electron mobilities indicate that Coulomb scattering is important even in extremely narrow quantum wells.