Diamond-like carbon films deposited by femtosecond laser pulses

Abstract

Hydrogen-free DLC films has been deposited by femtosecond laser pulse onto (1 0 0) p-type silicon substrates. The laser used for deposition has a pulse energy from 0.4mJ to1.6mJ and pulse width of about 50 fs with the repetition rate of 1 kHz. The laser intensities on the target are from 0.7×10¹⁴W/cm² to 2.8×10¹⁴W/cm². Uniform and wear-resistant DLC films is deposited with fs laser ablating a high purity graphite target at room temperature in vacuum. It is shown that the films has a good hardness ranged from 20 GPa to 30 GPa. Raman spectroscopy, X-ray Photoelectron Spectroscopy and micro-hardness are used to analyze the comprehensive performance of the films, and the results show that the films deposited at the laser intensity of 1.4×10¹⁴W/cm² has better hardness and a higher sp³ content. The sp³ fraction of the films is estimated to be as high as 45.6%.