Chemical Vapor Deposition of Boron‐Incorporated Graphitic Carbon Nitride Film for Carbon‐Based Wide Bandgap Semiconductor Materials

Abstract

This article discusses the growth of B atoms incorporated into the graphitic carbon nitride (g-C 3 N 4 ) thin films on c-plane sapphire substrates at various growth temperatures by thermal chemical vapor deposition (CVD) using melamine and ammonia borane as precursors. The B incorporation is achieved at a growth temperature of 618 C, which is slightly higher than the optimal growth temperature of g-C 3 N 4 thin films. The signal peak for the B 1s core level attributed to B-N bonds is observed by X-ray photoelectron spectroscopy, indicating the realization of B incorporation into g-C 3 N 4 films. With an increase in the growth temperature up to 650 C, a monotonically increasing B composition and a decreasing C composition are observed, implying that B atoms are incorporated into g-C 3 N 4 by the substitution into C sites. A shift of photoluminescene (PL) peak energy is observed. The PL peak shifts from 2.75 eV for unintentionally doped thin film to 3.60 eV for B-incorporated thin films with a composition of 8.0%. The B composition dependence of PL peak energies is in good agreement with the quadratic function, suggesting that the bandgap bowing occurs due to B incorporation into the g-C 3 N 4 thin films as in conventional compound semiconductor alloys.

Recent Progress on Photoelectrochemical Water Splitting of Graphitic Carbon Nitride (g−CN) Electrodes

“…Therefore, to control additional atoms composition and band-gap energy, the influence of pyrolysis conditions on additional atoms incorporation into the C–N network should be expounded. Inspired by these facts, Urakami and co-workers [ 110 ] reported a simple thermal chemical vapor deposition (CVD) route to prepare the B-incorporated g−CN film by employing ammonia borane (H 3 N–BH 3 ) as the B source. It was also noted that the pyrolysis temperature had an intimate connection with the compositional ratios, and the preferable temperature for B doping ranged from 618 °C to 650 °C ( Figure 9 d).…”

Thermal chemical vapor deposition of layered carbon nitride films under a hydrogen gas atmosphere

“…The synthesis of a boron-incorporated carbon nitride alloy with a composition below 8% has been realized, exhibiting a shift in luminescence and absorption color from blue (2.8 eV) to near-ultraviolet (3.6 eV). 20,21 In contrast, S-doped g-C 3 N 4 mesoporous powder with C-site substitution exhibits a narrow energy bandgap of approximately 2.6 eV. 22 In addition, a new energy state of optical absorption at a lower energy than that of the absorption edge was observed when the synthesized powder was thermally treated under a hydrogen (H 2 ) gas atmosphere.…”