Electrical response in atomic layer deposited Al:ZnO with varying stack thickness

摘要

We report on the effects of stacking of the macrocycles in atomic layer deposited (ALD) Al:ZnO thin films on the structural and electrical properties. There is a large change in the resistivity ranging from as high as 1.19 × 10~(-3) Ω cm for 760 growth cycles film down to as low as 7.9 × 10~(-4) Ω cm for the 4000 cycles. The electrical transport demonstrates a transition from a semiconductor behavior at 760 cycles to a metallic behavior in the 4000 cycle, due to an increase in electron scattering as well as increase in the carrier concentration. However, interestingly the carrier concentration sharply increases with increasing macrocycles containing Al and Zn, exhibiting a nearly metal-like behavior in thicker films. We anticipate that the change in Zn-vacancy, V_(zn), formation energy is related to the increase in surface area of the ALD precursor deposition plane. The increase in V_(zn) density allows for more adsorption of Al-precursor into the doped monolayer, showing interesting electrical properties.