Structural and electrical properties of carbon-ion-implanted ultrananocrystalline diamond films

• 来源期刊: 中国物理B（英文版）
• 关键词: ultrananocrystalline diamond C-ion implantation annealing electrical properties
• 年，卷（期）: 2018,（9）
• 页码范围: 483-491
• 页数: 9页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/9/096104

摘要

We investigate the structural and electrical properties of carbon-ion-implanted ultrananocrystalline diamond(UNCD)films.Impedance spectroscopy measurements show that the impedance of diamond grains is relatively stable,while that of grain boundaries(GBs)(Rb)significantly increases after the C+ implantation,and decreases with the increase in the annealing temperature(Ta)from 650 ℃ to 1000 ℃.This implies that the C+ implantation has a more significant impact on the conductivity of GBs.Conductive atomic force microscopy demonstrates that the number of conductive sites increases in GB regions at Ta above 900 ℃,owing to the formation of a nanographitic phase confirmed by high-resolution transmission electronic microscopy.Visible-light Raman spectra show that resistive trans-polyacetylene oligomers desorb from GBs at Ta above 900 ℃,which leads to lower Rb of samples annealed at 900 and 1000 ℃.With the increase in Ta to 1000 ℃,diamond grains become smaller with longer GBs modified by a more ordered nanographitic phase,supplying more conductive sites and leading to a lower Rb.