Doping of nanocrystalline silicon with sulfur by gas-phase diffusion

• Published in: Inorganic chemistry communications 2022-07, Vol.141, p.109602, Article 109602
• Main Authors: Popelensky, V.M., Chernysheva, G.S., Kononov, N.N., Bubenov, S.S., Vinokurov, A.A., Dorofeev, S.G.
• Format: Article
• Language: English
• Subjects: Doping; Nanosilicon; Semiconductor; Sulfur; Vapor-Liquid-Solid process
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2022.109602

[Display omitted] •Sulfur-doped nanosilicon particles were synthesized by gas-phase diffusion.•Maximum dopant concentration of 0.5 % mol. was achieved at 700 °C.•Crystalline silicon rods form at 900 °C, up to 300 μm long.•Synthesized at 900 °C sample has a direct bandgap transitions with energy of 1.09 and 1.69 eV.•Synthesized at 900 °C sample was found to show high conductivity and stability. Sulfur-doped silicon nanoparticles were synthesized by annealing of nanosilicon powder in sulfur vapors at 500, 700 and 900 °C. The structures, chemical composition, optical and electrical properties of the samples were characterized using transmission electron microscopy, scanning electron microscopy, total x-ray fluorescence, x-ray diffraction, electron diffraction and absorption spectroscopy. The highest sulfur concentration was achieved at 700 °C with most of the dopant located on the surface, but it was evenly distributed inside the particles’ cores. Maximum level of doping equals to 0.5 % mol of sulfur, which is 4 orders of magnitude higher than the equilibrium solubility at 700 °C. Moreover, silicon microwires up to 300 μm long were discovered in samples synthesized at 900 °C. These samples also exhibits unusual properties, like direct band gap absorption and good conductivity even after being stored under air for a long time.