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

作　　者：Xiao-Yan Liu Lei Wang Yi Tong 刘晓艳;王磊;童祎(College of Electronic and Optical Engineering&College of Microelectronics,Nanjing University of Posts and Telecommunications,Nanjing 210023,China)

机构地区：[1]College of Electronic and Optical Engineering&College of Microelectronics,Nanjing University of Posts and Telecommunications,Nanjing 210023,China

出　　处：《Chinese Physics B》2022年第1期434-444,共11页中国物理B（英文版）

基　　金：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);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/cm^(3),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 

分 类 号：O484.4[理学—固体物理]