Hole confinement in boron δ-doped Si quantum wells studied by admittance spectroscopy

Abstract

The admittance spectroscopy technique has been used to study the hole confinement in boron δ-doped Si quantum wells. A carrier thermal emission model is proposed to derive the activation energies of holes confined in the quantum wells from the measured conductance spectra. For the same peak doping concentration, the conductance peak shifts towards higher temperatures as the thickness of the δ-doped layer increases. The activation energies obtained from the measurements coincide well with the results of a self-consistent calculation of the subbands in the quantum wells. It verifies that the conductance peaks correspond to the hole emissions from the hole ground states in the δ-quantum wells to the Si valence band.