Space-charge-limited current in nanowires depleted by oxygen adsorption

The effects of oxygen adsorption on the conductivity and carrier transport mechanisms in CdS nanowires were established through variable temperature electrical transport and photoconductivity measurements. n-type CdS nanowires were found to be significantly less conductive in the ambient air than in the vacuum due to electron depletion induced by adsorbed oxygen. The current-voltage characteristics of depleted nanowires exhibited a power law behavior consistent with space-charge-limited conduction in the presence of traps. Analysis of the voltage and temperature dependencies of the space-charge-limited current showed that the nanowire surface traps are exponentially distributed in energy with a characteristic depth of similar to 0.28 +/- 0.04 eV. (c) 2006 American Institute of Physics.