Thermal phase stability of rhombohedral boron nitride

Solozhenko, Vladimir L.; Petrusha, І. A.; Svirid, A. A.

doi:10.1080/08957959608240463

Cited by 16 publications

(7 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1(b). This is supported by experimental studies by Solozhenko et al 36 The relative thermodynamic stability of the four BN polytypes previously derived from first-principles approach by Yu et al 30 and Solozhenko et al 37 suggested c-BN to be the most thermodynamically stable phase at ambient conditions. We attribute this discrepancy to our results to be a consequence of the inclusion of correction factors for long-range van der Waals interactions between the BN sheets in the sp 2 -hybridized polytypes h-BN and r-BN.…”

Section: Discussionmentioning

confidence: 61%

Thermodynamic stability of hexagonal and rhombohedral boron nitride under chemical vapor deposition conditions from van der Waals corrected first principles calculations

Pedersen

Alling

Högberg

et al. 2019

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

View full text Add to dashboard Cite

Thin films of boron nitride (BN), particularly the sp 2-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp 2-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium. 2 I. INTRODUCTION Cubic BN (c-BN) with sp 3-hybridization and diamond structure is the most wellknown among BN phases. In 1957, Wentorf synthesized c-BN from a mixture of boron and nitrogen at high temperature and pressures. 1 The discovery of "Borazon" catalyzed work on the other polytypes of BN, foremost sp 2-hybridized hexagonal BN (h-BN) "white graphite" and to some extent the less studied wurtzite form (w-BN) that is similar to "hexagonal diamond". In addition to h-BN a rhombohedral sp 2-hybridized BN phase (r-BN) was reported 1958 by Hérold. 2 The two sp 2-hybridized BN polytypes differ in their stacking sequence of the basal planes along the c-axis; h-BN exhibits an ABAB... stacking while r-BN has an ABCABC... stacking sequence. 3 Furthermore, the basal planes in h-BN are rotated 180°, with respect to the previous basal plane, around the caxis ([0001]), while in r-BN, each next basal plane is instead shifted along the direction by 1.45 Å. The very close structural similarity between h-BN and r-BN is demonstrated in identical in-plane lattice parameters, 2.504 Å, and spacing between the basal planes, 3.333 Å. 4 As a thin film, BN is a promising material for many electronic applications, 5-8 where the polytype, h-BN or r-BN, are likely to affect the electronic properties: h-BN is reported to have a slightly larger band gap than r-BN; 5.955 9 and 5.7 10 eV, respectively. Typically, sp 2-BN films have been deposited by thermally activated Chemical Vapor Deposition (CVD), i.e. close to thermal equilibrium conditions. Epitaxial growth of sp 2-BN thin films by CVD is typically carried out from triethylboron, B(C2H5)3 (TEB), and ammonia, NH3 at low pressures of 1000-10000 Pa and temperatures in the range of 1100-1500 °C (1400-1800 K). 11 The high temperatures needed limit the number of available substrate materials, thus, growth of epitaxial films has been restricted to α-Al2O3 (0001) and 4H/6H-SiC (0001) substrates, yielding films oriented around the caxis. 12-15 sp 2-BN as a two-dimensional material will consist of a single basal plane with hexagonal symmetry and it is therefore, correctly, refer to as h-BN. However, the authors have previously pointed out the difficulty in structural determination of sp 2-BN films gro...

show abstract

Section: Discussionmentioning

confidence: 61%

Thermodynamic stability of hexagonal and rhombohedral boron nitride under chemical vapor deposition conditions from van der Waals corrected first principles calculations

Pedersen

Alling

Högberg

et al. 2019

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

View full text Add to dashboard Cite

show abstract

“…Additionally, the thermo-mechanical conditions during LWH processing are not conducive for transformation from wurtzite to cubic phase material. Such a transformation (wBN -> cBN) requires temperature around 1200e1500 C and high pressures of 6e8 GPa [33]. The presence of water, impurities, and inclusions could reduce the pressure needed for such transformation as transformation of amorphous BN to cBN in the presence of water is reported to occur at 5.5 GPa [34] but transformation is not expected at the temperature and stress magnitudes applied during the LWJ processing.…”

Section: Discussionmentioning

confidence: 96%

Ultrahard boron nitride material through a hybrid laser/waterjet based surface treatment

et al. 2016

View full text Add to dashboard Cite

“…science.sciencemag.org/cgi/content/full/science.abd3230/DC1 Materials and Methods Figs. S1 to S26 Table S1 References (42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)…”

Section: Supplementary Materialsmentioning

confidence: 99%

Stacking-engineered ferroelectricity in bilayer boron nitride

Yasuda

Wang

Watanabe

et al. 2021

Science

534

424

View full text Add to dashboard Cite

2D ferroelectrics with robust polarization down to atomic thicknesses provide building blocks for functional heterostructures. Experimental realization remains challenging because of the requirement of a layered polar crystal. Here, we demonstrate a rational design approach to engineering 2D ferroelectrics from a non-ferroelectric parent compound via employing van der Waals assembly. Parallel-stacked bilayer boron nitride exhibits out-of-plane electric polarization that reverses depending on the stacking order. The polarization switching is probed via the resistance of an adjacently stacked graphene sheet. Twisting the boron nitride sheets by a small angle changes the dynamics of switching thanks to the formation of moiré ferroelectricity with staggered polarization. The ferroelectricity persists to room temperature while keeping the high mobility of graphene, paving the way for potential ultrathin nonvolatile memory applications.

show abstract

Thermal phase stability of rhombohedral boron nitride

Cited by 16 publications

References 10 publications

Thermodynamic stability of hexagonal and rhombohedral boron nitride under chemical vapor deposition conditions from van der Waals corrected first principles calculations

Thermodynamic stability of hexagonal and rhombohedral boron nitride under chemical vapor deposition conditions from van der Waals corrected first principles calculations

Ultrahard boron nitride material through a hybrid laser/waterjet based surface treatment

Stacking-engineered ferroelectricity in bilayer boron nitride

Contact Info

Product

Resources

About