Ultraviolet laser photolysis of hydrocarbons for nondiamond carbon suppression in chemical vapor deposition of diamond films

Authors

Li-Sha Fan, University of Nebraska-LincolnFollow
Loic Constantin, University of Nebraska-LincolnFollow
Da-wei Li, University of Nebraska-LincolnFollow
Lei Liu, University of Nebraska-LincolnFollow
Kamran Keramatnejad, University of Nebraska-LincolnFollow
Clio Azina, University of Nebraska-LincolnFollow
Xi Huang, University of Nebraska-LincolnFollow
Hossein Rabiee Golgir, University of Nebraska-Lincoln
Yao Lu, University of Nebraska-LincolnFollow
Zahra Ahmadi, University of Nebraska-LincolnFollow
Fei Wang, University of Nebraska-LincolnFollow
Jeffrey E. Shield, University of Nebraska-LincolnFollow
Bai Cui, University of Nebraska-LincolnFollow
Jean-Francois Silvain, Institut de Chimie de la Matière Condensée de Bordeaux
Yong-Feng Lu, University of Nebraska-LincolnFollow

Date of this Version

2018

Citation

Light: Science & Applications (2018) 7, 17177

Comments

Copyright The Author(s) 2018

Open access

doi:10.1038/lsa.2017.177

Abstract

In this work, we demonstrate that ultraviolet (UV) laser photolysis of hydrocarbon species alters the flame chemistry such that it promotes the diamond growth rate and film quality. Optical emission spectroscopy and laser-induced fluorescence demonstrate that direct UV laser irradiation of a diamond-forming combustion flame produces a large amount of reactive species that play critical roles in diamond growth, thereby leading to enhanced diamond growth. The diamond growth rate is more than doubled, and diamond quality is improved by 4.2%. Investigation of the diamond nucleation process suggests that the diamond nucleation time is significantly shortened and nondiamond carbon accumulation is greatly suppressed with UV laser irradiation of the combustion flame in a laser-parallel-to-substrate geometry. A narrow amorphous carbon transition zone, averaging 4 nm in thickness, is identified at the film–substrate interface area using transmission electron microscopy, confirming the suppression effect of UV laser irradiation on nondiamond carbon formation. The discovery of the advantages of UV photochemistry in diamond growth is of great significance for vastly improving the synthesis of a broad range of technically important materials.