Characterization of porous silicon light emitting diodes in high current density conditions

Experimental current-voltage and current-light intensity characteristics of Schottky diodes with the structure: metal (Al) - porous silicon - n-type silicon substrate are presented. The measurements are carried out with a pulsed current in the high current densities conditions, which usually lead to irreversible breakdown and damage the junctions if applied in continuous operation. Conditions and mechanism of Schottky diodes breakdown, based on avalanche multiplication of carriers, are analyzed and the limit of stimulating pulses duration, not yet leading to irreversible breakdown, is calculated. A microsecond current power pulses generator was designed and used to investigate the porous silicon light emitting diodes in the 2000...8000 A/cm(2) current density range. An explanation of the registered behaviour of the current-light intensity plots is presented.