Growth of nano-crystalline diamond by pulsed laser deposition in oxygen atmosphere

Abstract

Growth of nano-crystalline diamond by pulsed laser deposition (PLD) in an oxygen atmosphere on a sapphire (0 0 0 1) substrate is reported. The experiments were performed at a substrate temperature of ∼550°C and in an oxygen pressure of 0.11–0.15 Torr. Field-emission scanning electron microscope, X-ray diffraction and micro-Raman spectroscopy were used to characterize the products. Results indicated that hexagonal and cubic diamond crystals with an average size of ∼30 nm were formed. The crystal nucleation and growth were non-uniform and discontinuous. The possible diamond growth mechanism by PLD in an oxygen environment is discussed. Compared with diamond growth in a chemical-vapor-deposition process, the conditions for diamond nucleation and growth by PLD in an oxygen atmosphere are quite critical.