Visible electroluminescence from porous silicon np heterojunction diodes

Abstract

We report the preparation of silicon‐based visible light‐emitting diodes, configured as heterojunctions between porous silicon (formed by electrochemical etching of p‐type silicon wafers), and n‐type indium tin oxide (ITO). The transparent ITO film allows light emission through the top surface of the device, under a forward electrical bias of several volts across the junction. Photogenerated currents are observed under reverse biases. A tentative model for this electroluminescence is presented, based on injection of minority carriers through a narrow interphase region into the porous silicon structure, where radiative recombination occurs.