The facet orientation can be determined by high-resolution AFM measurements. Here, we want to notice that the fidelity of AFM imaging of nanostructures decreases with increasing slope of the sidewall facets due to the limitations in feedback gain and distortions caused by the tip-sample convolution.

Moreover, the small area size of the main sector facets in comparison with the tip radius (≤7 nm) limits the number of experimental points to be used for facet hkl indexing. Figure 3a presents the surface orientation map obtained from the AFM image shown in Figure 3b. These maps are Nepicastat obtained by calculating the normal vector for each image point using the nearest-neighboring image points [28, 29]. Each normal vector is determined by the polar coordinates (θ, φ) of the [hkl] vectors, where θ is the inclination angle between [hkl] and the [001] substrate normal

https://www.selleckchem.com/products/jph203.html and φ denotes the in-plane azimuth angle of the [hkl] vector with respect to the [100] substrate direction. Besides all the experimental constraints, zones with accumulation of points clearly appear in Figure 3a. The polar coordinates of these point accumulation zones can be assigned to several families of planes: 011, 113, 124, and 112 (indicated in the map by circle, square, triangle, and diamond symbols, respectively). The brightest spot at the center (not labeled) corresponds to the (001) surface plane. Although our experimental results point out that the steep wall close to the deep hole would be indexed as 112, the experimental Metalloexopeptidase constraints (AFM tip geometry and main sector size) could distort the experimental measurements and the true facet would be steeper than 112. Figure 2 AFM images of ringlike structures before and after As exposure of Ga droplets. (a) 600 × 300 nm2

AFM image of the ring structure, formed at a substrate temperature of 500°C, remaining after the Ga droplet was removed by HCl. (b) 3D representation of the ring structure. (c) 600 × 300 nm2 AFM image of the ring structure and nanohole obtained after annealing the Ga droplet under an As flux of 0.70 ML/s for 30 s. (d) 3D image of the same structure where the facets of the highest structure (main sector) surrounding the ring are clearly seen. Figure 3 YH25448 mouse Calculated surface orientation map, 3D planar view representation, and scheme of the main sector structure. (a) Calculated surface orientation map from the AFM image of the main sector similar to that shown in Figure 2d. The arrows indicate the increasing direction of the polar coordinates (θ, φ) of the [hkl] vectors. Empty symbols mark the family planes present. (b) 3D planar view representation of the AFM image where the facet edges have been highlighted by dashed lines. (c) Scheme of the main sector structure obtained from the surface orientation map with the facet indexing corresponding to the different family planes.