Confocal Raman spectroscopic study of the heteroepitaxial diamond growth on Pt(111)

We have characterized heteroepitaxial diamond on Pt(111) using the non-destructive technique of confocal Raman spectroscopy to investigate the variation in structure and strain with depth. The spectral depth profiles of isolated heteroepitaxial diamond crystal showed the sharp diamond peak at 1332 cm(-1), while those of nonepitaxial diamond crystal showed the diamond peak, as well as three bands centered at 1400, 1500 and 1530-1580 cm(-1). Various nondiamond phases were present in the nonepitaxial diamond crystals from the initial stage of diamond growth. The spectral depth profiles of heteroepitaxial diamond film showed the diamond peak at 1332-1335 cm(-1) and four bands centered at 1230, 1470-1490, 1530-1580 and 1640 cm(-1) near the surface. The diamond peak shifted to the single crystal peak position at 1332 cm(-1) as the linewidth was broadened with free surface proximity. The compressive strain in the heteroepitaxial diamond crystal decreased and turned into the random strain. At the same time, the Raman band at 1470-1490 cm(-1) grew in intensity. The constituents of nondiamond phase in the heteroepitaxial growth regions are different from those formed in the randomly oriented regions. (C) 1998 Elsevier Science S.A.