HPHT Synthesis of Phosphorus Doped Diamond from Triphenylphosphine and Graphite

Phosphorus doped diamonds have attracted great attentions in recent decades because of their n-type semiconductor properties. Most of them can be successfully produced by chemical vapor deposition (CVD) method. However, at high pressure high temperature (HPHT) conditions, the P-doped diamonds only obtained from carbon solution in phosphorus melt. We explored a new route to synthesize P-doped diamond. The diamond has been synthesized at 19 GPa and 1800 degree C for 1 min in a multi-anvil apparatus by using triphenylphosphine [P(C(6)H(5))(3)] and graphite as starting materials. The molar ratio of P to C was 1:100. The X-ray diffraction confirmed the existence of the diamond. The diamond crystallite size was determined to be about 14 nm. The Raman spectroscopy revealed a large shift in the diamond peak position between the sample (1326.9 cm(-1)) and the pure diamond (1332 cm(-1)). It may be caused by the phosphorus doping. The further studies are in progress.