Electronic properties of surfaces, subsurface layers and interfaces for semiconductor and semimetal solid solutions

Abstract

The electronic and physical-chemical properties of restorded (dDX≤0.5−1.0 nm) surfaces at the depth of the space-charge region and of semiconductor(semimetal)-native anodic oxide (dDX=1.0−100 nm) interfaces have been investigated by the combined field effect in electrolytes (CFEE) method at T = 273−305 K and in metal-oxide-semiconductor (MOS) systems at T = 77−305 K for monocrystalline solid solutions CdxHg1−xTe (0≤x≤0.4) and MnxHg1−xTe (0≤x≤0.24). The interpretation of experimental capacitance-potential and current-potential characteristics has been effectuated allowing for the degeneracy of the electron-hole gas and conduction band non-parabolicity (considered in the Kane approximation). The electronic properties of the surface and subsurface regions have been determined: the forbidden zone (Eg), the thermodynamic equilibrium (ni) and non-equilibrium (nix) carrier concentrations for intrinsic material or the doping level (NA,D) for extrinsic material, the density-of- states effective masses (mcx, mhx), the equilibrium semiconductor(semimetal) surface potential (Vs0) and total electric charge captured at the interface defects (Qtot0), the fast surface states (FSS) density (NSS). The FSS density and the total electric charge at the interface (Qtotox) increase drastically (0.5–2 orders) as a function of the anodic oxide thickness at dOX < 8−12 nm.