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Published online: 14 October 2009 | doi:10.1038/nchina.2009.203

Plasma physics: Diamond trees

Felix Cheung

Introduction

© (2009) AIP

Chemical vapour deposition (CVD) is a popular method for growing synthetic diamond. It involves ionizing a mixture of hydrocarbon gases — typically methane and hydrogen — inside a vacuum chamber to form a plasma cloud of macroscopic particles that are capable of self-organizing into diamond films or crystals.

Xiaodong Zhu and co-workers at the University of Science and Technology of China in Hefei¹ have now grown diamond trees through CVD. They generated a methane–hydrogen plasma between a pair of metal plate electrodes inside a stainless-steel chamber; on the bottom plate electrode was placed a molybdenum substrate maintained at a temperature of 800 °C. Given sufficient time, a diamond film would form on the substrate.

After allowing the system to run for tens of hours, the researchers observed the formation of clusters of diamond trees (pictured) around the edges of the substrate. Some trees reached 8 cm in length, with a growth rate of approximately 1.5 mm per hour. Scanning tunnelling microscopy revealed that the trees consisted of diamond on the outside, but graphitic carbon on the inside.

The findings demonstrate the possibility of using CVD for the rapid growth of complex diamond structures.

The authors of this work are from:
CAS Key Laboratory of Basic Plasma Physics, Department of Modern Physics, University of Science and Technology of China, Hefei, China.

Reference

1. Ding, F. et al. Branched carbon treelike structures grown in direct current plasmas. Appl. Phys. Lett. 95, 121501 (2009). | Article | ChemPort |