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

GARCES F.A.; RAÚL URTEAGA; LEANDRO N. ACQUAROLI; R.R. KOROPECKI; R.D. ARCE

Nanoscale Research Letters

Springer

Año: 2012 vol. 7 p. 1 - 16

1556-276X

We study the electrical characteristics of macroporous silicon/transparent conductor oxidejunctions obtained by the deposition of fluorine doped-SnO2 onto macroporous siliconthin films using the spray pyrolysis technique. Macroporous silicon was prepared by theelectrochemical anodization of a silicon wafer to produce pore sizes ranging between 0.9to 1.2 m in diameter. Scanning electronic microscopy was performed to confirm the porefilling and surface coverage. The transport of charge carriers through the interface wasstudied by measuring the current-voltage curves in the dark and under illumination. In thebest configuration, we obtain a modest open-circuit voltage of about 70 mV and ashort-circuit current of 3.5 mA/cm2 at an illumination of 110 mW/cm2. In order toanalyze the effects of the illumination on the electrical properties of the junction, weproposed a model of two opposing diodes, each one associated with an independentcurrent source. We obtain a good accordance between the experimental data and themodel. The current-voltage curves in illuminated conditions are well fitted with the sameparameters obtained in the dark where only the photocurrent intensities in the diodes arefree parameters.