CHARGE-TRANSPORT IN POROUS SILICON - CONSIDERATIONS FOR ACHIEVEMENT OF EFFICIENT ELECTROLUMINESCENCE

We have critically evaluated the mechanism of charge transport, the un derstanding of which is crucial for construction of porous silicon ele ctroluminescent devices. Multiple transport paths or space-charge-limi ted effects in porous silicon give rise to complex field dependence of the transport activation energy (E(A) = 0.38-0.67 eV). Direct correla tion between the chemical composition of the internal surface of silic on nanocrystallites and the charge transport properties is demonstrate d and the role of the tail states is emphasized. Recommendations for e fficient electroluminescence, based on the microstructure and drift le ngth, are summarized.