Fig. 1. Schematic diagram of material, strain and thickness of each period of periodic superlattice

Fig. 2. Schematic diagram of material and structure of strain balanced superlattice

Fig. 3. Measured surface toughness of samples A and B ( measurement range is 10 μm×10 μm). (a)-(e) Sample A; (f)-(j) sample B

Fig. 4. Schematic diagrams of growth modes and surface morphology characteristic of samples A and B. (a) Schematic diagram of step flow growth mode; (b) schematic diagram of FM growth mode; (c) surface morphology characterization of sample A (1 μm×1 μm); (d) surface morphology characterization of sample B (1 μm×1 μm)

Fig. 5. Comparison of PL curves of GaAs epitaxial layer of samples A and B. (a) Center; (b) right; (c) lower; (d) left; (e) upper

Fig. 6. XRD characterization curves of GaAs epitaxial layer of samples A and B

Table 1. Surface toughness of samples A and B

Table 2. PL intensity, FWHM and their mean value of samples A and B