Enhanced lifetime in porous silicon light-emitting diodes with fluorine doped tin oxide electrodes

We investigated the electrical and optical properties of porous Si (PS) light-emitting diodes using fluorinated tin oxide (FTO) as transparent electrodes. At high forward bias, the current–voltage characteristic is space charge limited. At low forward bias, it follows an exponential law. Whereas the electroluminescence (EL) in devices with non-fluorinated indium–tin oxide electrodes degrades in few minutes, EL intensity in devices with FTO electrodes shows little degradation after 1300 min of operation. This result indicates that the well known beneficial effects of fluorinated species in the improvement of resistance to irradiation and carrier injection degradation in metal–oxide–semiconductor devices might be also observed in PS devices.