Metal-semiconductor ohmic contacts: An ab initio Density Functional Theory study of the structural and electronic properties of metal-diamond (111)-(1 脳 1) interfaces
- 作者：I. Motochi ; ismotochi@gmail.com ; N.W. Makau ; G.O. Amolo
- 关键词：Diamond&ndash ; metal interfaces ; Adsorption ; Ohmic contacts
- 刊名：Diamond and Related Materials
- 出版年：2012
- 期刊代码：30_09259635
- 类别：ms
- 出版时间：March, 2012
- 卷：23
- 期：Complete
- 页码：10-17
- 文件大小：1823 K
摘要
Metal contacts on clean, hydrogenated and oxygenated diamond surfaces have been studied using ab initio Density Functional Theory (DFT). Five metals, i.e., gold, titanium, tantalum, vanadium and palladium on the three surfaces were considered. Gold and palladium were found to form weak bonds on clean, hydrogenated or oxygenated diamond (111) surfaces compared to the other three metals. Bulk properties were also studied following the formation of the respective ohmic contacts on the three surfaces. The clean diamond surface was found to have surface states which were modified by oxygen but removed by hydrogen. Density of states studies revealed that all the investigated metals had an effect on the electrical properties of the diamond surface. A peak that was characteristic of diamond was observed at 鈮堚垝11.8 eV. For the clean diamond surface terminated with gold and palladium, states due to Au-2p orbitals were observed at 鈭?#xA0;2.5 eV and 鈮堚垝1.5 eV, while Pd-5s orbitals were located at 鈮堚垝1.7 eV and 鈭?#xA0;0.5 eV on the same surface. Titanium, tantalum and vanadium showed unique states at high binding energies of 鈮堚垝38 eV for vanadium, 鈮堚垝34 eV for tantalum and 鈮堚垝32.5 eV for titanium, which were thought to be responsible for their strong bonding.