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

• Published in: Materials 2019-05, Vol.12 (11), p.1780
• Main Authors: Zhu, Rui, Tao, Qiang, Lian, Min, Feng, Xiaokang, Liu, Jiayu, Ye, Meiyan, Wang, Xin, Dong, Shushan, Cui, Tian, Zhu, Pinwen
• Format: Article
• Language: English
• Subjects: Boron; Carbon; Covalent bonds; Doping; Energy gap; Fluxing; Hybridization; Hydrogenation; Magnetron sputtering; Morphology; Nitrogen; Scanning electron microscopy; Spectrum analysis; Substrates
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma12111780

Amorphous carbon (a-C) films are attracting considerable attention to due their large optical band gap (E ) 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 E changing were analyzed by controlling the different experimental conditions of magnetron sputtering. A rapid deposition rate of 10.55 nm/min was obtained. The E is reduced from 3.19 eV to 2.78 eV by improving the substrate temperature and sputtering power. The proportion of sp /sp increasing was uncovered with narrowing the E . The shrinking E can be attributed to the fact that boron atoms act as a fluxing agent to promote carbon atoms to form sp hybridization at low energy. Furthermore, boron atoms can impede the formation of σ bonds in carbon atom sp hybridization by forming B-C bonds with high energy, and induce the sp hybridization transfer to sp hybridization. This work is significant to further study of amorphous semiconductor films.