Current-voltage characteristics in macroporous silicon/SiOx/SnO2:F heterojunctions

GARCÉS, F.; URTEAGA, R.; ACQUAROLI, L. N.; KOROPECKI, R. R.; ARCE, R. D.

NANOSCALE RESEARCH LETTERS

SPRINGER

Lugar: Berlin; Año: 2012 vol. 7 p. 419 - 425

1931-7573

We study the electrical characteristics of Macroporous Silicon/Transparent Conductor Oxide junctions obtained by the deposition of fluorine doped SnO2 onto macroporous silicon thin films, using the spray pyrolysis technique. Macroporous silicon was prepared by the electrochemical anodization of a silicon wafer to produce pores sizes ranging between 0.9 to 1.2 mum diameter. Scanning electronic microscopy was performed to confirm the pore filling and surface coverage. The transport of charge carriers through the interface was studied by measuring the current-voltage curves in dark and under illumination. In the best configuration we obtain a modest open circuit voltage of about 70 mV and a short circuit current of 3.5 mA/cm2 at illumination of 110 mW/cm2. In order to analyze the effects of the illumination on the electrical properties of the junction, we proposed a model of two opposing diodes, each one associated with an independent current source. We obtain a good accordance between experimental data and the model. The current-voltage curves on illumination conditions are well fitted with the same parameters obtained in dark where only the photocurrent intensities in the diodes are free parameters.