Fig. 3: Crystal quality analysis of InSb nanowires and the InSb/InP interface.

a Cross-section transmission electron microscope (TEM) image of an in-plane selective area (InSANe) InSb nanowire grown and imaged along the [−211] direction. Scale bar is 20 nm. b EDX map of a with P (green), Sb (red), and Si (blue) depicted showing the InSb nanowire, the InP substrate, and the Si_xN_y mask. The top of the mask is indicated by a white dash on the right; note that SiOx has been deposited on top of the sample to protect it during focused ion beam sample preparation. Scale bar is 20 nm. c Zoom-in on the InSb/InP interface in a (blue square) focusing on the atomic columns using an inverse fast Fourier transform (FFT) procedure filtered for the (110) periodicity. Scale bar is 1 nm. The vertical lines represent the columns of atoms which, at the interface of InSb/InP, show misfit dislocations, encircled in red. Counting the ratio of InSb columns and InP columns gives a lattice mismatch of 10.34%. d Fast Fourier transform of the InSb nanowire (a, green), the InSb/InP interface (a, blue), and the InP substrate (a, purple), demonstrating that the InSb and InP regions are both single crystalline. The FFT of the InSb/InP interface region shows double spots indicating two different lattice parameters. e Cross-section TEM image of an InSANe InSb nanowire grown and imaged along the [0–11] direction. Scale bar is 20 nm. f Zoom-in of e where a pair of horizontal twin planes can be observed a few nanometers above the InP/InSb interface. Scale bar is 5 nm. g Cut along a <112> direction grown wire, looking in the perpendicular <110> zone axis. A few nanometers above the InP/InSb interface, a horizontal twin plane can be observed along the entire observed length of the wire, indicated here by a red arrow. Scale bar is 20 nm.