Carrier transport by field enhanced thermal detrapping in Si nanocrystals thin films

The carrier transport at high voltage region in Si nanocrystal (SiNC) thin films has been investigated. The current-voltage measurements demonstrate that at high voltage region, conductance exponentially depends on V^1/2. The activation energy, measured from the temperature dependence of the current-voltage (I-^V) characteristics, decreases with an increase in the applied voltage. These results indicate that field enhanced detrapping dominates transport mechanism in the SiNC films at high voltage region. The possible influence of metal/semiconductor contacts on V^1/2 dependence has been excluded through the activation energy measurement on different work-function metals as electrodes. The position of the traps contributing to the detrapping processes is concluded to be at interfaces of SiNC/SiO ₂ since H₂ annealing drastically decreases the activation energy. The reasons why experimental results demonstrate no accordance with the material parameter V* of Poole-Frenkel expression have been discussed based on nanostructure characteristics of SiNC film.