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

Current-voltage characteristics of electroluminescent structures composed o f metal, erbium-doped amorphous silicon, and crystalline silicon and prepar ed by magnetron sputtering were measured and analyzed. It is shown that the carrier transport in a high-resistivity (a-Si:H):Er film (resistivity simi lar to 10(9) Ohm 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 (similar to 10(19) cm(-3) for both types of traps; 0.85-0.95 eV and 0.4 eV , respectively) are estimated by analyzing the current-voltage characterist ics. In the light of the results obtained, the published excitation mechani sm of erbium-related electroluminescence in such a material is discussed. ( C) 2000 MAIK "Nauka/Interperiodica".