Determination of band offsets in a-Si:H/c-Si heterojunctions from capacitance-voltage measurements:: Capabilities and limits

The capabilities and limitations of the well-known C-V technique for the determination of the conduction band offsets in (n)a-Si:H/(p)c-Si heterojunctions are presented. In particular, the effects due to the presence of an inversion layer in c-Si and a non-negligible defect density at the a-Si:H/c-Si interface on the reliability of the C-V intercept method are discussed. The influence of the Fermi level positions in (p)c-Si and (n)a-Si:H on the inversion layer formation and the influence of the interface defect density have been analysed using numerical simulations and experimental measurements. (C) 2007 Elsevier B.V. All rights reserved.