ELECTRICAL-CONDUCTIVITY OF AMORPHOUS-CARBON AND AMORPHOUS HYDROGENATED CARBON
ELECTRICAL-CONDUCTIVITY OF AMORPHOUS-CARBON AND AMORPHOUS HYDROGENATED CARBON
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DOI：
10.1080/13642819108205558
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发表时间：
1991-06-01
期刊：
影响因子：
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通讯作者：
TAGLIAFERRO, A
中科院分区：
文献类型：
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作者：
DASGUPTA, D;DEMICHELIS, F;TAGLIAFERRO, A
非晶碳（a-C）薄膜已通过射频制备。 Ar 气氛中石墨靶材的磁控溅射及其直流暗电导率已被测量为温度的函数。将结果与早期工作人员针对 a-C 和氢化 a-C 获得的结果进行了比较。详细分析使我们得出这样的结论：含或不含 H 的非晶 C 的电导率主要取决于材料中 sp2 位点的数量和分布。接近室温时，实验结果表明，如果 sp2:sp3 比率低于其逾渗阈值，则嵌入在 sp3（类金刚石）矩阵中的相邻 sp2（石墨）岛之间会发生跳跃；如果该比率高于该阈值，则会在带尾发生跳跃。在 500 K 以上的温度区域，带尾跳变被证明是唯一有效的机制。
Amorphous carbon (a-C) thin films have been prepared by r.f. magnetron sputtering of graphite targets in an Ar atmosphere and their d.c. electrical dark conductivity has been measured as a function of temperature. The results are compared with those obtained by earlier workers for a-C and hydrogenated a-C. A detailed analysis leads us to the conclusion that conductivity of amorphous C with or without H is determined mostly by the amount and distribution of sp2 sites in the material. Near room temperature the experimental results suggest hopping between neighbouring sp2 (graphitic) islands embedded in an sp3 (diamond-like) matrix if the sp2:sp3 ratio is below its percolation threshold value and hopping in the band tails if this ratio is above such a threshold. In the temperature region above 500 K hopping in the band tails is shown to be the only effective mechanism.