(a) Raman spectra and (b) Ge-V PL spectra of diamond particles growing under the different growth pressures. The inset is the Si-V PL spectrum of the diamond particles grown for 75 min under the growth pressure of 1.5 kPa. Dependence of (c) the diamond peak position and FWHM and (d) the Ge-V position and FWHM on the growth pressure.