Microstructural analysis of Nb-doped anatase TiO2 transparent conductive films by transmission electron microscopy

We investigated microstructures and transport properties of Nb-doped anatase TiO
₂
(TNO) films deposited by two methods: sputtering and pulsed laser deposition (PLD).We found that working pressure (P
_w
) of sputtering has a significant influence on both microstructures and transport properties. Cross-sectional observation by transmission electron microscopy revealed that lowered P
_w
improved homogeneity in the microstructure. This finding indicates that the inhomogeneous microstructure of the sputtered TNO films is not due to sputtering damage but to fluctuation in mass density. A sputtered film deposited at P
_w
= 0.50 Pa exhibited homogeneous microstructure and high Hall mobility comparable to those of PLD films.