Virtues of Ir(1 0 0) substrate on diamond epitaxial growth: First-principle calculation and XPS study

The heteroepitaxial growth of single crystal diamond requires substrate of high quality, and Ir(1 0 0) is an ideal substrate which can meet the standard perfectly. However, the reason of its outstanding performance still remains unclear. In this paper, the interaction mechanism between carbon atoms and Ir (1 0 0) surface at the initial stage of nucleation and its uniqueness caused by distinctive energy changes compared with (1 0 0) faces of Cu and Ni are explained by first-principle calculation, which acts as a dominating factor in the transformation from epitaxial films to single crystal wafers. The energy driving force of the dissolution-precipitation process is described, which can completely accord with bias-enhanced nucleation(BEN) method to illustrate the effect of voltage on diamond nucleation. The precipitation of carbon atoms and appearance of primary nuclei with the increase of carbon concentration are discussed, which can effectively explain the special phenomenon of the “domain” formation. A carbon-rich pre-treatment before primary nucleation on Ir (1 0 0) surface shows that the initial nucleation process can form supersaturated solid solution of carbon in Ir (1 0 0), which can greatly accelerate the subsequent dissolution-precipitation circulation.