Quantum oscillations in the magnetoresistance of GaAs δ (or planar) doped with Si are analyzed to obtain the electron densities of the electric subbands. We compare these densities with the results of self-consistently calculated subband structures of δ-doped GaAs in which the spread of the dopant atoms (Si) in the growth direction is a fitting parameter. The results indicate that there is negligible spread in structures grown at a substrate temperature TS ≲530°C, while in structures grown at higher TS there is measurable spread which increases with TS. For TS =640°C, the Si spread is determined to be ≅220 Å. An examination of the three-dimensional Si densities in these layers indicates that the dominant mechanism for the spreading of Si for TS >600°C is the migration of Si to satisfy the solid solubility limit.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)