Energetic and spatial distribution of grain boundary states in insb-bicrystals

G. Gobsch , Th. Schurig , W. Kraak , R. Herrmann , G. Paasch

The spatial and energetic distribution of grain boundary interface states in p-doped InSb-bicrystals with an n-inversion layer adjacent to the grain boundary is determined by fitting the calculated two-dimensional subband structure of the inversion layer to the experimentally obtained data. The total density of inversion electrons ns and the subband occupation nsi are established by magnetotransport measurements. A rapid decrease of ns is observed when hydrostatic pressure is applied. By analysing the pressure dependence of ns an energetic density of grain boundary states of 1.5 x 10^13 cm -2 eV-1 was evaluated for the energy range from the conduction band edge up to 90 meV above it. Calculations performed within a numerically simple model indicate the existence of two types of ionized grain boundary states : positively charged donorlike ones localized in the grain boundary core with a density of 4.22 x 10^12 cm-2 and negatively charged ones spatially more extended with 2.27 x 10^12 cm-2 . Some possible reasons for these interface states are discussed.

Keywords: bicrystals; grain boundaries; high pressure effects in solids; III V semiconductors; indium antimonide; interface electron states; inversion layers; magnetoresistance

Domains: Physics archives

G. Gobsch, Th. Schurig, W. Kraak, R. Herrmann, G. Paasch. Energetic and spatial distribution of grain boundary states in insb-bicrystals. Journal de Physique, 1989, 50 (3), pp.283-294. ⟨10.1051/jphys:01989005003028300⟩. ⟨jpa-00210918⟩