The influence of the interface state on the properties of solar cell semiconductor electrodes

An n-Fe/sub 2/O/sub 3/ film was grown on an n-Si substrate which had undergone surface treatment to form a double layer semiconductor electrode. The influence of the interface state on the electrode properties was studied. From photoluminescence measurements, we found that an interface state with high density of states exists lying above the top of the Fe/sub 2/O/sub 3/ valence band at 1.61 eV. The Fermi level is pinned by this interface state. Using energy band profiles, we give an explanation for the photoluminescence, as well as a theoretical calculation and analysis for the capacity-voltage curves and photo-current-voltage curves. These theoretically calculated curves agree well with the experimental data. This double layer semiconductor electrode with an interface state with high density of states is promising material for solar cells of good stability and high photo-electric conversion efficiency.