Fig. 1. Morphological change of patterned GaAs (001) substrate before and after deoxidation: (a) AFM image of flat GaAs after deoxidation; AFM image of patterned GaAs before (b) and after deoxidation (c), the trenches are orientated along direction and the sidewall inclination angle α₁ is about 16°; (d) AFM line-scans of the trenches before (black line) and after deoxidation (red line). GaAs (001)衬底与沿 方向的纳米沟槽脱氧前后的形貌变化　(a)脱氧后平衬底区域的AFM图; (b), (c) α₁ ≈ 16°时图形结构区域脱氧前后的AFM图; (d)沟槽脱氧前后AFM线扫描图

Fig. 2. Morphological change of the trenches (inclination angle α₁ ≈ 40° and orientated along direction) after GaAs buffer growth: (a), (b) AFM images of the trenches before and after the deposition of 30 nm GaAs buffer at low temperature; (c) the black and red lines represent the cross-sectional AFM line-scans of (a) and (b). α₁ ≈ 40° (black line); α₁ ≈ 39°, α₂ ≈ 19° (red line). 沿 方向倾斜角α₁ ≈ 40°时的纳米沟槽在GaAs缓冲层生长前后的形貌变化　(a), (b)低温外延30 nm GaAs缓冲层前后的AFM图; (c)生长前后沟槽的AFM线扫描图, 图中黑色曲线对应α₁ ≈ 40°, 红色曲线对应α₁ ≈ 39°, α₂ ≈ 19°

Fig. 3. Site-controlled growth of InAs QDs on patterned GaAs with trenches along direction. 沿 方向的纳米沟槽中InAs量子点优先成核位置分布图

Fig. 4. Dependence of preferential nucleation site of InAs QDs on trench inclination angle of the patterned GaAs.InAs量子点在GaAs纳米沟槽中优先成核位置与纳米沟槽侧壁倾斜角α₁的关系

Fig. 5. Orientational dependence of InAs QDs on trench-patterned GaAs along and [110]: (a) and (b) AFM images of InAs QDs grown on trench-patterned GaAs along and [110] with a trench inclination angle α₁ ≈ 18°. InAs QDs优先成核位置在相同倾斜角度不同方向的纳米沟槽中的各向异性　(a)和(b)分别为α₁≈18°时沿 和[110]方向纳米沟槽生长InAs量子点后的AFM图

Fig. 6. Site-controlled growth of InAs QDs molecules on pit-patterned GaAs (001) substrate: (a) Double InAs QDs molecules at the pits bottom; (b) four InAs QDs molecules in the pits; (c) QDs rings around the pits; (d) cross-sectional AFM line-scan of these pits. The inclination angles are 10°, 17°, 28°, respectively.调控纳米孔洞侧壁的倾斜角α₁实现不同InAs量子点组合的定位生长　(a)生长在纳米孔洞底部的双量子点分子; (b)生长在纳米沟槽侧壁上的四量子点, 其中插图示意四量子点的位置; (c)纳米孔洞外沿形成量子点环; (d)图(a), (b)和(c)中纳米孔洞的AFM线扫描图, 倾斜角分别为10°, 17°, 28°