(a) AFM image (left) and RHEED image (right) of SrTiO3 (001) substrate. (b) and (c) AFM, real-time RHEED oscillations and RHEED images of samples grown at 720 °C and 776 °C under 1 J/cm2 laser fluence. (d) AFM (upper left) and SEM (upper right) images of sample grown at 840 °C under 1 J/cm2 laser fluence. Mn (lower left) and O (lower right) EDX spectroscopy are shown corresponding to SEM image area.
Samples grown at different temperatures with laser fluence of 4 J/cm2. (a) and (b) surface morphologies of samples grown at 660 °C and 760 °C. (c) and (d) corresponding RHEED oscillations and image of sample in (b).
(a) Growth pressure dependence of surface morphology under growth temperature of 730 °C and laser fluence of 1 J/cm2. (b) Surface roughness (in unit of nm) map of the sample under oxygen pressure gradient. The dashed arrow indicates the direction of increasing local pressure.
Laser fluence dependence of samples grown at (a) 1 J/cm2 and (b) 2.2 J/cm2, both under growth temperature of 740 °C. (c) and (d) corresponding RHEED oscillations and image of the sample in (b).
Microscopic illustration of the growth processes. (a) Schematic diagram of the atomic process in the deposition. (b) Schematic of the poor crystalization (left) and the good crystalization (right). (c) Schematic of the 2D layer-by-layer growth and the 3D growth.
The theoretically constructed growth diagram. L1 (red): boundary between stoichiometric and non-stoichiometric growth; L2 (green): boundary between 2D layer-by-layer (LBL) and 3D growth; L3 (blue): boundary between the P-C and W-C growth.
Qualitative comparison between experimental results and theoretical growth diagram. Arrows description: dashed-dotted-dotted: temperature increase (720 °C, 776 °C, 840 °C) under constant laser fluence (1 J/cm2) and pressure; dashed-dotted: temperature increase (660 °C, 760 °C) under constant laser fluence (4 J/cm2) and pressure; long dashed: laser fluence increase (1 J/cm2, 2.2 J/cm2) under constant temperature and pressure; solid: pressure increase under constant temperature (730 °C) and laser fluence (1 J/cm2).
EDX analysis of non-stoichiometric sample (840 °C, 1 J/cm2).
Article metrics loading...
Full text loading...