Formation of defects in boron nitride by low energy ion bombardment

Abstract

Formation of defects in hexagonal and cubic boron nitride ͑h-BN and c-BN, respectively͒ under low-energy argon or nitrogen ion-bombardment has been studied by near-edge x-ray absorption fine structure ͑NEXAFS͒ around boron and nitrogen K-edges. Breaking of B-N bonds for both argon and nitrogen bombardment and formation of nitrogen vacancies, V N , has been identified from the B K-edge of both h-BN and c-BN, followed by the formation of molecular nitrogen, N 2 , at interstitial positions. The presence of N 2 produces an additional peak in photoemission spectra around N 1s core level and a sharp resonance in the low-resolution NEXAFS spectra around N K-edge, showing the characteristic vibrational fine structure in high-resolution measurements. In addition, several new peaks within the energy gap of BN, identified by NEXAFS around B and N K-edges, have been assigned to boron or nitrogen interstitials, in good agreement with theoretical predictions. Ion bombardment destroys the cubic phase of c-BN and produces a phase similar to a damaged hexagonal phase.

Point defects in hexagonal BN, BC3 and BCxN compounds studied by x-ray absorption near-edge structure

“…This is supported by an increasing defect concentration in the BCN structure, as confirmed by the increasing intensity of peaks assigned to oxygen decorated defects, mostly at energies above 192.0 eV. Recently, Petravic and coworkers [39][40][41] reported B1s XANES spectra of Ar þ and N 2 þ bombarded h-BN powders attached to a conductive C tape, which are very similar to our spectra of BC x N films with a high C content in Fig. 3.…”

“…Furthermore, new p* states are detected at the left of peak M, which are similar to peak L in the reference sample grown by PLD (N1s top panel). Jiménez et al, 26 and recent studies by Petravic and coworkers, [39][40][41] have claimed that this peak is due to localized states associated to interstitial nitrogen. As mentioned before, the intense N1s p* peak observed at 0 indicates the existence of randomly oriented N-B 3 environments.…”

“…37,38 Recently, a wider p* excitonic distribution (189-195 eV) with resolved X-Z peaks was detected after lowenergy Ar þ or N 2 þ ion-bombardment of h-BN crystalline powder attached to a carbon tape. [39][40][41] The X-Z peaks were assigned to a gradual increment of N-vacancies around the B atoms. 25,26 A similar explanation was given in a XANES study of BN nanotubes, while the intense Z peak was suggested to originate from unreacted boron oxide used in the preparation procedure.…”

Structure, stability and defects of single layer hexagonal BN in comparison to graphene

“…Deposition of graphene on h-BN is found to improve the transport properties of graphene possibly due to suppression of scattering from out of plane ripples [4]. The growth of thin BN films is known to require a certain amount of ion irradiation which in turn leads to the detrimental formation of point defects [5]. The presence of defects lead to special features in x-ray core level spectroscopy [5,6] which have stimulated the study of selected defects in h-BN by firstprinciples [7,8,9,10].…”

Mechanics and Mechanically Tunable Band Gap in Single-Layer Hexagonal Boron-Nitride

“…Young's modulus and Poisson's ratio v at lower strain reported here are comparable with previous investigations. [19,24] The antisite defects are uniquely seen in h-BN and have long been investigated by experiments [43,44] and theory. [13,[45][46][47][48] However, the effects of antisite defects on the mechanical properties of h-BN remain unclear.…”