Search

BN films were synthesized on the (100)-oriented surface of n-Si (0.008–0.02 Ωm) by rf magnetron sputtering physical vapor deposition (PVD). A BN film was first treated with H2 plasma for 60 min and then the H2 treated sample was treated with O2 plasma for 15 min. The films were characterizes by using Fourier transform infrared spectra (FTIR) and atomic force microscopy (AFM). The field emission characteristics of BN films were measured in an ultrahigh vacuum system. A turn-on electric field of 8 V/μm and a current of 400 μA/cm2 were obtained for the BN film treated with H2 plasma. The results show that the surface plasma treatment makes no apparent influence on the surface morphology of the BN films. The transformations of the sample emission characteristics have to do with the surface negative electron affinity (NEA) of the films possibly. The turn-on electric field of the BN film treated with H2 plasma is lower than that without treatment, which possibly attributes to the surface NEA effect. The surface NEA of the H2 treated BN film is lost after O2 plasma treatment.

Boron nitride (BN) thin films with cubic boron nitride (c-BN) phase were prepared on the (100)-oriented surface of n-Si (0.008–0.02 Ωm) by rf magnetron sputtering physical vapour deposition. The c-BN content is determined to be around 50% by using Fourier transform infrared spectroscopy for the BN thin films. The field emission characteristics of BN films were measured in an ultrahigh vacuum system. It is found that the field emission of the BN film with c-BN phase is evidently more excellent than that without c-BN phase. A turn-on field of 5 V/μm and a current of 460 μA/cm2 were obtained for the BN film with c-BN phase. The Fowler–Nordheim plots of emission characteristics of BN films indicate a straight line, which suggests the presence of the FN tunnelling.

Nanometre boron nitride (BN) thin films with various thickness (54-135 nm) were prepared on Si(100) by rf magnetic sputtering physical vapour deposition. The field emission characteristics of the BN thin films were measured in an ultrahigh vacuum system. A threshold electric field of 11 V/µm and the highest emission current density of 240 µA/cm2 at an electric field of 23 V/µm were obtained for the about 54-nm-thick BN film. The threshold electric field increases with increasing the thickness in the nanometre range. The Fowler-Nordheim plots show that electrons were emitted from BN to vacuum by tunnelling through the potential barrier at the surface of BN thin films.

The pressure dependences of the Raman-active graphite layer shearing modes in highly oriented pyrolytic graphite (HOPG) and FeCl3-HOPG acceptor intercalation compounds for stage indices n=1, 2 and 3 have been measured in diamond anvil cell by use of a Spex-1403 Ramalog system. The results of high-pressure Raman spectra show that both the interior and neighbouring modes exhibit a frequency shift upwards with increasing pressure, which has been attributed to an in-plane lattice contraction. In stage-3 FeCl3-HOPG, the pressure-induced staging transition from stage 3 to stage 4 has been found from the change in intensity ratio of the interior to neighbouring modes at 8.39 GPa. This finding confirmed firstly that the pressure-induced staging transitions are not just confined to the alkali-metal graphite donor intercalations but are valid for the acceptor graphite intercalation compounds.

We report a new method to prepare boron nitride (BN) thin films on Si (100) substrates in an Ar–N2-BCl3-H2 gas system by magnetron arc enhanced plasma chemical vapour deposition. Fourier transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) are used to characterize the films. The FTIR spectra show that the deposited boron nitride films experienced a transition from pure h-BN phase to a cubic-containing phase with the variation of arc current ranging from 10 A to 18 A. The BN film with 42% c-BN was obtained without substrate bias voltage. In the gas system of Ar–N2–BCl3–H2, h-BN can be preferentially etched by chlorine. The chemical etching effect of chlorine allows the formation of c-BN without substrate bias voltage, which may develop a new perspective for the deposition of high quality c-BN film with low stress.