Light-emissive nonvolatile memory effects in porous silicon diodes

It is demonstrated that there are distinct off and on states in the current -voltage characteristics of porous silicon (PS) diodes, and that the visibl e electroluminescence (EL) is observed in the on state. The PS diodes are c omposed of semitransparent thin Au films, rapid thermal oxidization (RTO)-t reated PS layers (similar to 0.5 mu m thick), p-type Si substrates, and ohm ic back contacts. After the PS layers were prepared by anodizing Si wafers in an ethanoic HF solution, the samples were treated by RTO process. The bi stable states of this PS diode can be simply and reversibly controlled by t he external bias voltage. Based on the behavior of the EL and capacitance-v oltage characteristics, the model of memory effect is presented, in which f ield-induced carrier injection and ejection into and from silicon nanocryst allites strongly affects the carrier transport. (C) 1999 American Institute of Physics. [S0003-6951(99)01101-8].