On the multi-channel conduction in β-In2S3 thin films

Nanocrystalline β-In2S3 thin films were grown using the chemical spray pyrolysis technique. Conductive AFM studies showed the presence of a conduction path through the core of the nano-crystallites which showed higher conductivity (an order) compared to the conduction path through the grain boundaries. The conduction path through the grain boundary material exhibited higher conductivity (2 orders) compared to the grain. The local current–voltage measurements carried out at the grain boundaries encapsulating the crystallites exhibited rectification behavior. The nano-crystalline thin films with conducting core showed persistent photoconductivity even when exposed to very low levels of light intensity. The persistent photoconductivity has been modeled based on the conducting core, insulating grain and conducting grain boundary identified in these thin films.