Growth of semiconductor/insulator structures: GaAs/fluoride/GaAs (001)

Thin single‐crystal layers (∼100–2000 A) of (001) oriented SrF2 and CaF2 have been grown onto clean MBE‐grown GaAs (001) surfaces. RED patterns suggest a significant difference in the interaction of CaF2 and SrF2 with clean reconstructed GaAs (001). Three‐dimensional behavior is suggested in the initial nucleation stages of CaF2 growth, although significant ordering occurs for film thickness >100 A. Nucleation of SrF2 on c(2×8) reconstructed GaAs surfaces results in a well‐ordered reconstructed (4×2) surface up to film thicknesses of ∼100 A, after which a disordered (1×1) unreconstructed surface is apparent. GaAs has been grown onto MBE prepared fluoride surfaces. At sufficiently low growth rates on CaF2, RED patterns indicate well ordered surfaces with (4×4) reconstruction. Increased deposition rates lead to twinned GaAs growth. Photoluminescence studies of undoped GaAs layers on SrF2 reveal a relatively sharp exciton structure with a full width at half‐maximum (FWHM) of 4 meV. Auger depth profile experi...