POROUS SILICON N-P LIGHT-EMITTING DIODE

A test device to implement room temperature visible light emitting dio des (LED) based on porous silicon (p-Si) is reported. The device is ob tained through a post processing electrochemical anodization of p-type doped Si wafers where n(+)-type stripes have been obtained by implant ation. This device differs with respect to others by the fact that the n(+)-type stripes are not floating on p-Si but are joined to the unde rlying p-type doped silicon by narrow crystalline stems which provide mechanical stability to the device and act as a thermal sink during di ode operation. A detailed characterization of the LED and comparison w ith a control LED (i.e. without the n(+)-type stripes) were carried ou t. A model of electrical injection, which aims to explain the electrol uminescence results and the observed differences between the proposed LED structure and the control LED, is also proposed. (C) 1997 Elsevier Science S.A.