Electronic and topographic structure of ta-C, ta-C:N and ta-C:B investigated by scanning tunnelling microscopy

被引：12

作者：

Arena, C ^{[1
]}

Kleinsorge, B ^{[1
]}

Robertson, J ^{[1
]}

Milne, WI ^{[1
]}

Welland, ME ^{[1
]}

机构：

[1] Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England

来源：

关键词：

doping; electronic states; scanning tunnelling microscopy; tetrahedral amorphous carbon;

D O I：

10.1016/S0925-9635(98)00267-2

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The electronic and topographic properties of undoped, nitrogen- and boron-doped tetrahedrally bonded amorphous carbon (ta-C) films have been investigated by scanning tunnelling microscopy (STM). The density of states (DOS) has been determined by scanning tunnelling spectroscopy (STS) measurements. The band edges were derived by STS by taking tangents to the generalized conductivity (dI/dV) within a certain energy window. The DOS shows that the valence band tail is sharper than the conduction band tail. A sp(2)-rich surface layer is found. For nitrogen-doped samples, the Fermi level is found to move towards the conduction band, confirming that n-type doping occurs. However, for boron-doped samples, there is no evidence of a shift of the Fermi level towards the valence band, suggesting that boron does not act as a dopant for ta-C. Topographic analysis showed very Aat samples (roughness RMS of the order of a few angstroms). Samples deposited on silicon were smoother, whereas spherical nanoparticles were found on samples deposited on metal. (C) 1999 Published by Elsevier Science S.A. All rights reserved.

引用

页码：435 / 439

页数：5

共 20 条

[1]

ARENA C, 1999, IN PRESS J APPL PHYS

[2]

CHOWALLA M, 1997, J APPL PHYS, V81, P139

[3]

Davis CA, 1995, SURF COAT TECH, V76, P316, DOI 10.1016/0257-8972(95)02553-7

[4] PROPERTIES OF FILTERED-ION-BEAM-DEPOSITED DIAMOND-LIKE CARBON AS A FUNCTION OF ION ENERGY [J].