Band offsets of epitaxial cubic boron nitride deposited on polycrystalline diamond via plasma-enhanced chemical vapor deposition

Abstract

Cubic boron nitride (c-BN) has been deposited on nitrogen-doped polycrystalline diamond films via plasma-enhanced chemical vapor deposition employing fluorine chemistry. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were utilized to characterize the c-BN/diamond interface. TEM observations indicated local epitaxy of c-BN on diamond, while h-BN was also observed at the interface. XPS measurements indicated that c-BN growth continued after nucleation. The band offsets between c-BN and diamond were deduced from XPS measurements. The c-BN valence band maximum (VBM) was 0.8 ± 0.1 eV above the diamond VBM, which corresponded to the c-BN conduction band minimum (CBM) of 1.7 ± 0.1 eV above the diamond CBM. Comparison with offsets predicted by theoretical calculations suggests that a C-N interface was obtained.

RETRACTED: Exploration of Growth Window for Phase-Pure Cubic Boron Nitride Films Prepared in a Pure N2 Plasma

“…Diamond has been reported as a perfect nucleation surface for epitaxial growth of c-BN due to the small lattice mismatch of these two materials [3,4,21,22]. Epitaxy of c-BN/diamond is attracting significant attention for both basic crystal engineering and optoelectronic applications.…”

The electronic properties and band-gap discontinuities at the cubic boron nitride/diamond hetero-interface

“…The latter is accordance to a recent report in which VBM of c-BN was inferred to be 0.8 eV above that of diamond for C-N interfacial bonding. 36 However, the previous theoretical calculations demonstrated that the c-BN VBM positioned at least 1.9 eV below the diamond VBM in the (100) surface for C-B bondings and 0.13 eV for C-N bondings. 35 In addition, the c-BN VBM was found to be 0.71 eV lower than that of diamond as to the (110) hetero-interface with one mixed C-B and C-N layer.…”

Electronic band offset in a diamond|cBN|diamond system for modulation doping

“…Experiments have already shown that along certain crystallographic orientations, [100] and [111], it is possible to grow a C|BN heterostructure. [28][29][30][31][32] Unlike the C|BN heterostructures of two bulk phases, [25,31,33] in present exploratory study a cBN "monolayer" is sandwiched, so the band offset between identical diamond phases is well defined (e.g., exactly zero in the absence of cBN)-convenient model to explore the offset dependence on crystallographic directions or BN thickness. We examine below how the cBN shifts the electronic band structure of diamond, and eventually facilitates the modulation doping, [34] assuming the free charge carriers and donors/acceptors would be in different diamond regions, separated by the cBN interface.…”