Porous silicon n-p light emitting diode

A test device to implement room temperature visible light emitting diodes (LED) based on porous silicon (p-Si) is reported. The device is obtained through a post processing electrochemical anodization of p-type doped Si wafers where n(+)-type stripes have been obtained by implantation. 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 underlying p-type doped silicon by narrow crystalline stems which provide mechanical stability to the device and act as a thermal sink during diode operation. A detailed characterization of the LED and comparison with a control LED (i.e. without the n(+)-type stripes) were carried out. A model of electrical injection, which aims to explain the electroluminescence results and the observed differences between the proposed LED structure and the control LED, is also proposed. (C) 1997 Elsevier Science S.A.