THE INCORPORATION OF NICKEL AND PHOSPHORUS DOPANTS INTO BORON-CARBON ALLOY THIN-FILMS

The structural and electronic properties of nickel- and phosphorus-dop ed boron-carbon (BSC) alloy thin films grown by plasma-enhanced chemic al vapor deposition have been examined. The Ni-doped boron-carbon allo ys were grown using closo-1,2-dicarbadodecaborane (C2B10H12) as the bo ron-carbon source compound and nickelocene (Ni(C5H5)(2)) as the nickel source. The phosphorus-doped alloys were grown using the single-sourc e 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) (Ohm cm)(-1) and transfo rmed the material from a p-type semiconductor to an n-type. Phosphorus doping decreased the conductivity, relative to undoped B5C, by two or ders of magnitude and increased the band gap from 0.9 eV for the undop ed material to 2.6 eV. Infrared absorption spectra of the nickel- and phosphorus-doped B5C alloys were relatively unchanged from those of un doped B5C. X-ray diffraction suggests that the phosphorus-doped materi al may be a different polytype from the Ni-doped and undoped B5C alloy s.