Crystalline Boron Nanoribbons:  Synthesis and Characterization

Abstract

Catalyst-free growth of boron nanoribbons was observed by pyrolysis of diborane at 630−750 °C and ∼200 mTorr in a quartz tube furnace. Nanodiffraction analysis indicates the nanoribbons are single crystal α-tetragonal boron. TEM images show the nanoribbon is covered by a 1−2 nm thick amorphous layer. Elemental analysis by EELS, EDX, and XPS shows the nanoribbons consist of boron with small amounts of oxygen and carbon. Infrared and Raman spectra are also reported.

Synthesis of crystalline boron nanoribbons and calcium hexaboride nanowires by low pressure chemical vapor deposition

“…The main O 1s component is assigned to boron oxide. These assignments are generally in agreement with those of Xu et al [28].…”

“…Selected area electron diffraction shows that the nanoribbons are crystalline. Measured d-spacings from the SAED pattern (figure 3) are well matched by those in JDPDS file # 77-1275, which confirms that our product is α-tetragonal boron, a conclusion also reached by Xu et al [28]. Further information on the nature of the boron nanoribbons is provided by the Raman spectra in figure 4.…”

“…The peak at 520 cm -1 is due to the silicon substrate. All of the peaks reported by Xu et al [28] are within a few cm -1 of the peaks that we observe, with the exception of their peaks at 705 and 746 cm -1 , which are not seen in our spectra. Also, we observe additional peaks that are not apparent in their spectra, indicating that additional boron phases are present in our samples.…”

“…Further information on the nature of the boron nanoribbons is provided by the Raman spectra in figure 4. Table 1 compares the peaks reported by Xu et al [28] with those observed here. The peak at 520 cm -1 is due to the silicon substrate.…”

Electronic structures and mechanical properties of boron and boron-rich crystals (Part 2)

“…Even in well-studied graphite, a new phase with monoclinic structure was found [46]. Among nanostructure materials, new phases have been discovered, such as boron nanowires [47], nanobelts [48], and nanoribbons [49]. The success of synthesizing BC 5 by Solozhenko et al shows that even unstable compounds, which do not appear in the phase diagram, can be synthesized under special circumstances [50].…”