IONIZED IMPURITY SCATTERING IN PERIODICALLY DELTA-DOPED INP

The quantum mobility in the individual minibands of InP with periodic Si delta doping was estimated from the Shubnikov-de Haas spectra of th e samples, measured at 3.2 K in fields of 0-14 T. The set of samples s tudied had a sheet density of Si atoms of about 4.9 x 10(12) cm(-2) in each doped layer, and 3 doping period in the range 90-300 Angstrom. A theoretical model for the quantum mobility in individual minibands wa s developed. and theoretical estimates of the quantum mobility an in r easonable agreement with the experimental values. It is observed that at a fixed doping period the quantum mobilities increase with the inde x of the miniband. and the quantum mobility in an individual miniband decreases when the doping period is made shorter, The dependence of th e quantum mobility on the miniband index and doping periodicity correl ates with the dependence of the mean distance between electrons and th e doped layer on the same quantities. These results demonstrate that i n delta-doped semiconductors the binding length of the quantum-confine d electronic charge is a very important parameter, determining the car rier mobility which can be attained in these systems.