Modulating Band Gap of Boron Doping in Amorphous Carbon Nano-Film

Abstract

Amorphous carbon (a-C) films are attracting considerable attention to due their large optical band gap (Eopt) range of 1–4 eV. But the hopping conducting mechanism of boron doping a-C (a-C:B) is still mysterious. To exploring the intrinsic reasons behind the semiconductor properties of a-C:B, in this work, the boron doping a-C (a-C:B) nano-film was prepared, and the growth rate and Eopt changing were analyzed by controlling the different experimental conditions of magnetron sputtering. A rapid deposition rate of 10.55 nm/min was obtained. The Eopt is reduced from 3.19 eV to 2.78 eV by improving the substrate temperature and sputtering power. The proportion of sp2/sp3 increasing was uncovered with narrowing the Eopt. The shrinking Eopt can be attributed to the fact that boron atoms act as a fluxing agent to promote carbon atoms to form sp2 hybridization at low energy. Furthermore, boron atoms can impede the formation of σ bonds in carbon atom sp3 hybridization by forming B–C bonds with high energy, and induce the sp3 hybridization transfer to sp2 hybridization. This work is significant to further study of amorphous semiconductor films.

Insights into the High Catalytic Activity of Li‐Ion Battery Waste toward Oxygen Reduction to Hydrogen Peroxide

“…284.0 eV corresponding to the carbon atoms forming C−C bonds in the graphite sheets (sp 2 ) [49] . Another peak in the binding energy range from 285.5 to 286.7 appears, which can be assigned to carbon with sp 3 hybridization, where the carbon atoms are bonded to heteroatoms like oxygen (C−O) or nitrogen (C−N) [50] or to hydrogen (C−H) [51] . Next, peaks in the interval from about 288.0 eV to about 289.7 eV can be ascribed to the carbon of carbonyl C=O and O=C‐OH groups (e. g., quinone groups) [52] or oxygen functionalities resulting from carbon surface oxidation during leaching [50] .…”

One-step recovery of REE oxalates in electro-leaching of spent NdFeB magnets

“…9c). Established boron peak is centered at a binding energy of (191.5 ± 0.1) eV after 1 h of electrolysis and corresponds to B2O3 [39,40]. Increasing time of electrolysis to 2 h leads to disappearing of boron from coating surface.…”

Structural Analysis of Boron- and Nitrogen-Doped Amorphous Carbon Films from Bio-Product

“…Doping bonds can also be shown from the C1s spectrum. In boron doping, B-C bonds are found at 283.2 eV [7]. In nitrogen, peaks can form at 285.8 and 287.5 eV which show two C-N bond structures, namely N-sp 2 C and N-sp 3 C bonds [11].…”

“…The process of adding a controlled impurity to a semiconductor is known as doping. In recent years, many researchers have carried out doping processes on a-C films with donors like Nitrogen [6] and acceptors like Boron [7] to form n-type and p-type, respectively. With the n-type and p-type amorphous carbon film, it can be used to make p-n junction in solar cell applications [8].…”

“…To obtain information about the structure and chemical state of the amorphous carbon and its doping atoms, synchrotron photoemission spectroscopy (PES) is often used [7,9,10,11]. Information about the bonding state is acquired from the spectral regions of C1s, B1s (for doping B), and N1s (for doping N).…”