Evaluation of size and its distribution of InP nanowires using small angle X-ray scattering and X-ray diffraction at the grazing condition

The structure of vertical InP nanowires on InP (111)B were investigated using grazing incidence X-ray diffraction and grazing incidence small angle X-ray scattering. The size distribution of the nanowires was evaluated from the diffuse scattering at (22~0) diffraction and analyzed using a cylinder model. The average diameter was about 15 nm, which was 10 nm smaller than that in the SEM observation. This can be explained by an oxide layer on the nanowire's sidewall. Nanowire height was investigated using grazing incidence small angle X-ray scattering. Sharp streaks along the horizontal axis were observed, suggesting the formation of nanowires with uniform height. Form the distance between streaks, the average height of the nanowires was determined and the length of nanowires was estimated to be about 700 nm, which was consistent with the SEM observation.