Current injection mechanism for porous-silicon transparent surface light-emitting diodes

We present a model for the injection of minority carriers into porous silicon films which results in visible dc electroluminescence. A thin interfacial dielectric region is postulated between the surface of the porous silicon layer and a transparent conductive oxide on the surface, which allows alignment of states between the two corresponding conduction bands of these materials under bias, and hence, overlap of electron wave functions and the passage of a tunneling current. Interface state densities are calculated and a parasitic nonradiative shunt current through such states is discussed.