微晶
无定形固体
材料科学
碳纤维
纳米技术
结晶学
复合材料
化学
冶金
复合数
作者
Shichao Zhao,Yimeng Zhao,Chenghao Deng,Lujun Pan
标识
DOI:10.1016/j.mtnano.2022.100207
摘要
Polycrystalline-amorphous carbon nancoils (CNCs) have been discovered and studied for years. Herein, carrier mobility ( μ ) and concentration ( n ) of CNCs are probed for the first time, using electric field regulation and finite element analysis, which are calculated to be 21 cm 2 /Vs and 1.6×10 19 cm -3 at room temperature. Temperature dependence characterization from 290 to 350 K reveals 0.8 to 1.6 folds increase of μ , but only 5%∼14% increase of electrical conductivity. This determines a significant decrease of n with temperature increasing. Variable X-ray diffraction characterization attributes this illogical decrease of n to the thermal expansion in c-axis direction of sp 2 grains, when there are abundant vacancies in CNCs providing spaces for the expansion. Upon expansion, the compression of the space between sp 2 grains results in reduced carrier scattering and increased μ . The weakened atomic interaction in a sp 2 grain increases band gap and decreases density of state, determining the decrease of n . Four-electrode characterization along the length direction of single CNCs uncovers a decrease (increase) tendency of μ ( n ) along with the growth process, which clarifies a negative (positive) relation between defect level and μ ( n ), and predicts the potential optoelectronic applications of CNCs.
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