B.J. Offrein, G.L. Bona, et al.
IEEE Photonics Technology Letters
We report the direct measurement of dopant and carrier density profiles in GaAs (001) modulation-doped structures using cross-sectional scanning tunneling microscopy. On ultrahigh-vacuum-cleaved cross-sectional (110) GaAs surfaces, individual electrically active dopants are observed as hillocks in the top several surface layers, and the tip-sample separation is found to be sensitive to the carrier concentration. In structures where the conventionally measured p-type dopant concentration varied from 1×1018 to 1×1019 cm-3 the density of such dopant hillocks varies accordingly and the tip-sample separation changes by 0.1 nm.
B.J. Offrein, G.L. Bona, et al.
IEEE Photonics Technology Letters
J.D. Crow, L. Comerford, et al.
Proceedings of SPIE 1989
M. Johnson, U. Maier, et al.
Journal of Crystal Growth
B.J. Offrein, F. Horst, et al.
IEEE Photonics Technology Letters