TEM analysis of the container effect of Au‐based catalyst droplets during vapour‐liquid‐solid growth of axial ZnTe/CdTe nanowires

Abstract

Axial heterostructure nanowires (NWs) of ZnTe/CdTe were grown by vapour-liquid-solid growth realized in a molecular beam epitaxial chamber. By alternative supply of Zn or Cd and constant Te the heterostructure was generated. The liquid phase is provided by a Au-based eutectic droplet which stays at the tip of the NW during the entire growth. For structural and chemical characterization by TEM the NWs were harvested from the substrate and transferred to a holey carbon film. The NWs exhibit an expansion of the diameter correlated with the interface region between ZnTe and CdTe. Idiomorphic growth of the CdTe is evident from electron diffraction experiments. The growth rate of CdTe appears to be smaller compared to that of ZnTe at the same temperature. Both, quantitative high-resolution TEM and energy dispersive X-ray spectroscopy line scans reveal a smeared ZnTe/CdTe interface along about 200 nm. The smearing is due to both, the liquid catalyst which buffers the supply of Cd instead of Zn at the liquid/solid interface and to the strain which is induced by the lattice mismatch. It forces the system to consume the remnant Zn for the NW growth in favour of Cd. Dedicated to Prof. Wolfgang Neumann on the occasion of his 65th birthday

Residual strain in free-standing CdTe nanowires overgrown with HgTe

“…Although no Zn is applied for the actual CdTe wire growth, it remains solved in the catalytic droplet seeding the growth and gets slowly consumed during the ongoing crystal growth. 16 In addition, we see that the ω position of the reflections in tilt of 0.5 • towards [001] for all reflections investigated. This can be explained by a bending of the NWs directly after the ZnTe growth start.…”

One-Pot Synthesis of Liquid Hg/Solid β-HgS Metal−Semiconductor Heterostructures with Unique Electrical Properties

“…After 48 h of reaction, β-HgS begins to generate and grow on the surface of Hg NS (Figure b). In general, an exact 1D structure is formed originating from a single droplet, which follows a typical liquid−solid growth mechanism, so a β-HgS tail with a sharp end is formed on the surface of every Hg NS herein. Moreover, the longer the reaction time is, the longer the tail is (Figure b−d).…”

Precise strain mapping of nano-twinned axial ZnTe/CdTe hetero-nanowires by scanning nanobeam electron diffraction

“…The irregular shape is a typical for ZnTe/CdTe axial hetero-NWs. In the work [54], this was explained by the difference in nucleation energy for the growth of ZnTe and CdTe parts.…”