Thickness dependent metal-insulator transition and dimensional crossover for weak localization in Si0.02Zn0.98O thin films grown by pulsed laser deposition

Metal to insulator transition was observed in Si0.02Zn0.98O (SZO) films, grown by pulsed laser deposition on sapphire substrates, as the thicknesses of the films were reduced from similar to 40 to 15 nm. The SZO film with thickness of similar to 40 nm showed typical metallic behavior in temperature dependent resistivity measurements. On the contrary, the SZO film with thickness of similar to 15 nm was found to exhibit strong localization where the transport at low temperature was dominated by variable range hopping conduction. In the intermediate thickness regime, quantum corrections were important and a dimensional crossover from 3D to 2D weak localization occurred in the SZO film with thickness of 20 nm. (C) 2014 AIP Publishing LLC.