The incorporation of Nickel and Phosphorus dopants into Boron-Carbon alloy thin films

5

C) alloy thin films grown by plasma-enhanced chemical vapor deposition have been examined. The Ni-doped boron–carbon alloys were grown using closo-1,2-dicarbadodecaborane (C₂B₁₀H₁₂) as the boron–carbon source compound and nickelocene(Ni(C₅H₅)₂) as the nickel source. The phosphorus-doped alloys were grown using the single-source compound: dimeric chloro-phospha(III)-carborane ([C₂B₁₀H₁₀PCl]₂). Nickel doping increased the conductivity, relative to undoped B₅C, by six orders of magnitude from 10^-9 to 10^-3 (Ω cm)^-1 and transformed the material from a p-type semiconductor to an n-type. Phosphorus doping decreased the conductivity, relative to undoped B₅C, by two orders of magnitude and increased the band gap from 0.9 eV for the undoped material to 2.6 eV. Infrared absorption spectra of the nickel- and phosphorus-doped B₅C alloys were relatively unchanged from those of undoped B₅C. X-ray diffraction suggests that the phosphorus-doped material may be a different polytype from the Ni-doped and undoped B₅C alloys.