p-type hexagonal boron nitride films with bis(cyclopentadienyl) magnesium as a doping gas in halide vapor phase epitaxy

Abstract

We report an in situ carbon doping method for fabricating p-type hexagonal boron nitride thin films with a halide vapor phase epitaxy system by introducing bis(cyclopentadienyl) magnesium as a doping gas. The hBN films exhibited a growth rate of 3 μm/h, while the doped hBN films showed a considerable reduction in resistivity by 8 orders of magnitude. Hall measurements demonstrated that the doped hBN films were p-type conductive. At room temperature, the doped hBN films exhibited a free hole concentration of ∼1015 cm−3 and a resistivity of about 1000 Ω cm. X-ray photoelectron spectroscopy demonstrated the doping of carbon impurities into the hBN films and the formation of chemical bonds with B by mainly replacing nitrogen. Temperature-dependent I–V properties indicated that the ionization energy of the carbon impurities was about 320 meV.