Health & Environmental Research Online (HERO)


Print Feedback Export to File
6017422 
Journal Article 
Diamond heteroepitaxy: pattern formation and mechanisms 
Golding, B; Bednarski-Meinke, C; Dai, Z 
2004 
Yes 
Diamond and Related Materials
ISSN: 0925-9635 
Elsevier 
13 
4-8 
545-551 
WOS:000221691100002 
Pattern formation that occurs during the initial condensation of diamond can provide insights into the physical mechanisms responsible for crystal growth. From a practical perspective, it can be exploited to develop reliable heteroepitaxial growth processes. Using (001) Ir on sapphire (α-Al2O3) or strontium titanate (SrTiO3) as substrate, and a methane–hydrogen plasma in the presence of d.c. bias, we reproducibly generate dense arrays, 1012 cm−2, of orientationally-ordered (001) diamond nanocrystallites. They appear on the Ir substrate after the rapid quench brought about by abrupt bias termination. The crystallite sizes are highly monodisperse, with typical lateral size below 10 nm. Under the appropriate conditions, the nascent diamond crystals self-organize into a lattice with six-fold coordination and correlation lengths of several lattice parameters. The regularity of the patterns raises the possibility of a collective instability of the excited carbon condensate. Since the crystallite density is so high, subsequent growth leads to rapid coalescence within a few minutes, resulting in a smooth, continuous film that covers the substrate. When the growth step is extended in time, thick single crystal plates have been grown over areas approaching 1 cm2. Particular emphasis is placed on the time evolution of emergent patterns during the bias stage, early coarsening of diamond grains, and the textures during extended growth. These results are placed in the context of dynamical systems driven far from equilibrium. 
single crystal growth; heteroepitaxy; nucleation; microstructure