TRANSPORT-PROPERTIES OF SELF-SUPPORTING POROUS SILICON

We present the results of the first transient and steady-state photoco nductivity measurements on self-supporting (19 mu m thick) porous sili con (PS) sample. The value of the free-carrier photogeneration quantum efficiency (eta) is discussed together with the mobility-lifetime pro duct, deduced from transient (mu(D) tau(D)) and steady-state photocurr ent (mu tau)(ss). Surprisingly (mu tau)(ss) much less than (mu(D) tau( D)).From very similar spectral dependence and the magnitude of the ste ady-state photocurrents measured in the sandwich and coplanar geometri es, we conclude that the ''tissue'' controlled transport in PS is almo st isotropic.