Measurement of the density of gap states in hydrogenated amorphous silicon by space charge spectroscopy

A critical assessment of the Mott-Schottky analysis for the characterisation of passive film-electrolyte junctions

“…Such a value of effec tive electron mass has been chosen in order to keep the ΔE F ≥ 3 k B T as requested by the simplified M-S theory for the validity of Eq. (21). A still larger effective elec tron mass (m* ≈ 22) is necessary to keep the constraint ΔE F ≥ 3k B T, if we used the value of donor density (~5 × 10 19 cm -3 ) derived from M-S plots in the high band bending regime.…”

“…and the conduc tion band edge, E C , if we assume the theory of crystal line semiconductor. In this last case the location of conduction band edge it is carried out by means of equation: (21) where ΔE F represents the distance in energy of the conduction band from the Fermi level of the semicon ductor, N C, eff is the effective density of states at the conduction band edge and N D is the density of donor derived from the M-S plots.…”

“…In recent papers [5,[16][17][18][19] we have suggested that the theory of amorphous semiconductor (a SC) Schottky barrier [20][21][22][23][24] is able to explain in a very large range of electrode potential and ac frequencies both the EIS spectra as well as the behaviour of both component of admittance as a function of electrode potential of thin and thick films of semiconducting anodic oxide film grown on different metals (Ti, Nb, W). However the use of a rather complex equivalent circuit in EIS study as well the limited range of acces sible frequencies and electrode potentials although confirmed, in our opinion, the validity of the theory of a SC Schottky barrier hampered a more direct com parison of M-S theory and a SC Schottky barrier in the interpretation of the experimental results.…”

Defect Spectroscopy on Damp-Heat Treated ZnO/CdS/Cu(In,Ga)(S,Se)2/Mo Heterojunction Solar Cells

“…Lang et al [41] point out that the surface of the absorber does not have the form of just a monolayer of atoms, but rather represents a transition region to the bulk semiconductor. Taking advantage of capacitance spectroscopy and DLTS, it seems to be impossible to distinguish whether a certain kind of defect is located directly at the surface layer or inside a thin interface region.…”

Identifying electronic properties relevant to improving the performance and stability of amorphous silicon-based mid-gap and low-gap cells: Annual subcontract report, 16 January 1998--15 January 1999

“…Such measurements provide us with an estimate of our film thickness (the temperature independent capacitance region at low T is simply related to the geometric thickness, d, by the formula C = εA/d), and an Arrhenius plot of the frequency of the lowest temperature capacitance step (or conductance peak) vs. 1/T provides us with the activation energy of the ac conductivity, E σ , which we identify with the Fermi energy position: E σ = E C -E F . [8] These admittance measurements also give us an indication of the quality of our Schottky barriers which allow us to pre-screen our samples for further study.…”