As shown in Figure , the root mean square roughness (RMS) of LNO is 3.75 nm, while the RSM of LNO-Vo (Figure ) and LNO-Vo' (Figure ) is 4.14 nm and 0.85 nm, respectively. This variation shows that introducing oxygen vacancies by controlling the partial pressure of oxygen during film growth led to an increase in the RSM of the films, while the particle size and morphology of LNO-Vo (Figure ) did not change significantly compared to those of LNO (Figure ). The increased RSM of LNO-Vo is due to the appearance of oxygen vacancies during sample preparation, which has been also observed in ZnO epitaxial thin films. However, introducing oxygen vacancies by H2 annealing led to a significant decrease in the RSM of the films (Figure ). The decrease of RSM of LNO-Vo' is attributed to the reorganization of the surface during the H2 annealing process. More importantly, the AFM 3D images reveal that the LNO-Vo' (Figure ) samples show a more pronounced island structure compared to LNO (Figure ) and LNO-Vo (Figure ), attributed to the H2 treatment leading to the reorganization of the LNO surface.