INPLANE EFFECTIVE MASSES AND QUANTUM SCATTERING TIMES OF ELECTRONS INNARROW 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 th e respective bulk data. This result is in good agreement with recent t heoretical calculations which predict an increase of m(parallel-to) w ith decreasing well width. The scatter of the mass values for nominall y identical quantum wells is assumed to reflect corresponding variatio ns of the well widths. The ratio of quantum to classical scattering ti mes and the carrier density dependence of the electron mobilities indi cate that Coulomb scattering is important even in extremely narrow qua ntum wells.