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Room‐temperature, solution‐processed, silicon nanoparticle thin films show significant gating with distinct hysteresis in their current–voltage characteristics. Device performance strongly depends on measurement environment and charge transport is determined by particle surfaces. Particle encapsulation with polymethyl methacrylate or Al2O3 reduces hysteresis and device sensitivity against environmental influences. Both Al2O3 coating and UV exposure during measurements alter current transport and enhance conductivity, providing evidence for surface‐dominated transport.

In this work, the capability of gas phase synthesis for crystal shape engineering of silicon nanoparticles (SiNPs) in a hot wall reactor is demonstrated. Therefore, the necessary boundary conditions for the formation of monodisperse spherical SiNPs as well as octahedral-shaped particles from silane pyrolysis are systematically deduced. The different shapes of the SiNPs are ascribed to different growth regimes (reaction limitation, diffusion limitation) depending on the global process parameters. Single crystalline, defect-free, spherical particles with a mean diameter of 30 nm (geometric standard deviation below 1.1) and octahedra with a mean edge length of about 100 nm could be obtained solely by process parameter adjustment. Particle size and shape as well as crystallinity were characterized by scanning electron microscopy and X-ray diffraction. The inner structure and faceting of the particles were analyzed in detail by high resolution transmission electron microscopy. A model that elucidates the orientation relation between the inner silicon structure and the particle shape is derived for the octahedra.

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