中国物理B ›› 2022, Vol. 31 ›› Issue (1): 16102-016102.doi: 10.1088/1674-1056/ac0cd8

• • 上一篇    下一篇

First-principles study of structural and opto-electronic characteristics of ultra-thin amorphous carbon films

Xiao-Yan Liu(刘晓艳), Lei Wang(王磊), and Yi Tong(童祎)   

  1. College of Electronic and Optical Engineering&College of Microelectronics, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
  • 收稿日期:2021-01-29 修回日期:2021-06-10 接受日期:2021-06-21 出版日期:2021-12-03 发布日期:2021-12-23
  • 通讯作者: Lei Wang, Yi Tong E-mail:LeiWang1980@njupt.edu.cn;TongYi@njupt.edu.cn
  • 基金资助:
    Project supported by the NUPTSF (Grant Nos. NY220078, NY217116, and NY220112), the Science Foundation of Jiangsu Province, China (Grant Nos. BK20211273 and BZ2021031), the Dual Innovative Doctor of Jiangsu Province, China (Grant No. JSSCBS20210522), the Institution of Jiangsu Province, China (Grant No. 20KJB510014), the National and Local Joint Engineering Laboratory of RF and Micro-assembly (Grant No. KFJJ20200203), the Industry Program of Huzhou City (Grant No. 2020GG03), the Distinguished Professor Grant of Jiangsu Province, China (Grant No. RK106STP18003), the Jiangsu Province Research Foundation, China (Grant Nos. NLXZYZZ219001 and SZDG2020009), the National Natural Science Foundation of China (Grant No. 61964012), and the Foundation of Jiangxi Science and Technology Department, China (Grant No. 20202ACBL212001).

First-principles study of structural and opto-electronic characteristics of ultra-thin amorphous carbon films

Xiao-Yan Liu(刘晓艳), Lei Wang(王磊), and Yi Tong(童祎)   

  1. College of Electronic and Optical Engineering&College of Microelectronics, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
  • Received:2021-01-29 Revised:2021-06-10 Accepted:2021-06-21 Online:2021-12-03 Published:2021-12-23
  • Contact: Lei Wang, Yi Tong E-mail:LeiWang1980@njupt.edu.cn;TongYi@njupt.edu.cn
  • Supported by:
    Project supported by the NUPTSF (Grant Nos. NY220078, NY217116, and NY220112), the Science Foundation of Jiangsu Province, China (Grant Nos. BK20211273 and BZ2021031), the Dual Innovative Doctor of Jiangsu Province, China (Grant No. JSSCBS20210522), the Institution of Jiangsu Province, China (Grant No. 20KJB510014), the National and Local Joint Engineering Laboratory of RF and Micro-assembly (Grant No. KFJJ20200203), the Industry Program of Huzhou City (Grant No. 2020GG03), the Distinguished Professor Grant of Jiangsu Province, China (Grant No. RK106STP18003), the Jiangsu Province Research Foundation, China (Grant Nos. NLXZYZZ219001 and SZDG2020009), the National Natural Science Foundation of China (Grant No. 61964012), and the Foundation of Jiangxi Science and Technology Department, China (Grant No. 20202ACBL212001).

摘要: Most amorphous carbon (a-C) applications require films with ultra-thin thicknesses; however, the electronic structure and opto-electronic characteristics of such films remain unclear so far. To address this issue, we developed a theoretical model based on the density functional theory and molecular dynamic simulations, in order to calculate the electronic structure and opto-electronic characteristics of the ultra-thin a-C films at different densities and temperatures. Temperature was found to have a weak influence over the resulting electronic structure and opto-electronic characteristics, whereas density had a significant influence on these aspects. The volume fraction of sp3 bonding increased with density, whereas that of sp2 bonding initially increased, reached a peak value of 2.52 g/cm3, and then decreased rapidly. Moreover, the extinction coefficients of the ultra-thin a-C films were found to be density-sensitive in the long-wavelength regime. This implies that switching the volume ratio of sp2 to sp3 bonding can effectively alter the transmittances of ultra-thin a-C films, and this can serve as a novel approach toward photonic memory applications. Nevertheless, the electrical resistivity of the ultra-thin a-C films appeared independent of temperature. This implicitly indicates that the electrical switching behavior of a-C films previously utilized for non-volatile storage applications is likely due to an electrically induced effect and not a purely thermal consequence.

关键词: amorphous carbon, density, optical properties, electronic structure, density functional theory

Abstract: Most amorphous carbon (a-C) applications require films with ultra-thin thicknesses; however, the electronic structure and opto-electronic characteristics of such films remain unclear so far. To address this issue, we developed a theoretical model based on the density functional theory and molecular dynamic simulations, in order to calculate the electronic structure and opto-electronic characteristics of the ultra-thin a-C films at different densities and temperatures. Temperature was found to have a weak influence over the resulting electronic structure and opto-electronic characteristics, whereas density had a significant influence on these aspects. The volume fraction of sp3 bonding increased with density, whereas that of sp2 bonding initially increased, reached a peak value of 2.52 g/cm3, and then decreased rapidly. Moreover, the extinction coefficients of the ultra-thin a-C films were found to be density-sensitive in the long-wavelength regime. This implies that switching the volume ratio of sp2 to sp3 bonding can effectively alter the transmittances of ultra-thin a-C films, and this can serve as a novel approach toward photonic memory applications. Nevertheless, the electrical resistivity of the ultra-thin a-C films appeared independent of temperature. This implicitly indicates that the electrical switching behavior of a-C films previously utilized for non-volatile storage applications is likely due to an electrically induced effect and not a purely thermal consequence.

Key words: amorphous carbon, density, optical properties, electronic structure, density functional theory

中图分类号:  (Amorphous semiconductors, metals, and alloys)

  • 61.43.Dq
81.05.U- (Carbon/carbon-based materials) 92.60.hv (Pressure, density, and temperature) 36.20.Kd (Electronic structure and spectra)