Formation of single and heterostructured nanowires based on $\mathrm{InAs}_{1-x}\mathrm{P}_x$ solid solutions on $\mathrm{Si}(111)$

We study the growth of nanowire arrays based on $\mathrm{InAsP}$ on silicon substrates. It was found that during the growth process two structural phases are formed: a cubic structure of the sphalerite type and a hexagonal structure of the wurtzite type. The epitaxial relations between $\mathrm{InAsP}$ and $\mathrm{Si}$ were determined: $[0001]_{ННК}||[111]_{\mathrm{Si}}$, $[11\bar20]_{ННК}||[1\bar10]_{\mathrm{Si}}$. A decrease of the radial growth rate and the formation of an axial heterojunction were revealed with the formation of thin ($< 100$ nm) segments of the $\mathrm{InAs}_{1-x}\mathrm{P}_x$ solid solution and maintaining a sufficiently high partial pressure of the $\mathrm{As}$ flow (at least $50$%).