Impact of atomic layer deposition temperature on electrical and optical properties of ZnO:Al films

Abstract

This work highlights the impact of growth temperature on electrical and optical properties of Al-doped ZnO (AZO) films deposited by atomic layer deposition (ALD) technique. The ALD process and super-cycle sequence have been optimized, identifying their influence on film resistivity. By using this optimum ALD procedure, the optical and electrical properties of AZO films have been widely analyzed considering the deposition temperature. Results show promising values with film resistivity in the range of 1 mΩcm and average optical absorption below 2% for 50 nm thick AZO layers. Hall effect, X-ray diffraction and ellipsometry measurements point out that these excellent values are related to their high carrier concentration and mobility, crystalline phase and optical band gap resulting in ALD AZO films with very good properties to be applied in photovoltaic devices as transparent conductive oxide electrode.