Current-voltage characteristics of electroluminescent Me/(a-Si:H):Er/c-Si structures prepared by magnetron sputtering

Current-voltage characteristics of electroluminescent structures composed of metal, erbium-doped amorphous silicon, and crystalline silicon and prepared by magnetron sputtering were measured and analyzed. It is shown that the carrier transport in a high-resistivity (a-Si:H):Er film (resistivity ∼109 Ω cm) proceeds by the mechanism of unipolar-injection space-charge-limited currents controlled by two types of traps. Trap parameters, namely, the densities and ionization energies of acceptor and donor centers (∼1019 cm−3 for both types of traps; 0.85–0.95 eV and 0.4 eV, respectively) are estimated by analyzing the current-voltage characteristics. In the light of the results obtained, the published excitation mechanism of erbium-related electroluminescence in such a material is discussed.