Surface features of self-organized SrTiO₃ (001) substrates inclined in [100] and [110] directions

The dependence of self-organized surface features in inclined SrTiO ₃ (001) substrates such as step edge, step height, and terrace width on the inclined angle from 0° to 6° and inclined direction of [100] and [1 1 0] were investigated. Wavy step edges, straight step edges, and triangular step edges are formed in the flat, the [100], and the [1 1 0] inclined substrates, respectively. The average step height increases with the inclined angle, while the average terrace width decreases. The steps on the inclined substrates after self-organization increase, but the same ratio of step height to terrace width is conserved when the inclined angle is constant. These behaviors in surface features of the self-organized substrate with inclined angles are closely related to the step interaction energy required to form the step height and terrace width. The inclined angle and the inclined direction should be important factors for controlling nanostructure morphology.