ELECTRICAL, PHOTOELECTRICAL AND ELECTROLUMINESCENT PROPERTIES OF POROUS SI-C-SI HETEROJUNCTIONS

Porous silicon-c-Si heterojunctions have been formed by the method of stain etching. A ZnO highly conductive thin film was used as a front t ransparent contact. The transport mechanism, photovoltaic and electrol uminescent properties have been studied. The heterojunctions show a wi de spectral response, from 400 to 1000 nm. The spectral dependence of the photocurrent in the region 400-600 nm depends on the reverse bias. Electroluminescence from the device structure in the visible region h as been observed under forward bias. A model based on tunneling of min ority carriers through a narrow energy barrier between ZnO and porous Si and the presence of a spike barrier and a conduction band discontin uity at the interface porous Si/c-Si is suggested for describing the p roperties of the heterojunctions. (C) 1997 Elsevier Science S.A.