Evidence for Ge-C Bond Formation at High P-T Conditions in a Laser Heated Diamond Anvil Cell

GexC1-x is expected to be a wide band gap semi conductor. But the synthesis of this material in bulk by conventional equilibrium methods at atmospheric pressure is not possible as it is not energetically favorable. In this paper we report evidence for formation of Ge-C bonds using Laser Heated Diamond Anvil Cell (LHDAC) technique at P similar to 9.3 GPa and similar to 2000 K after prolonged heating for similar to 30 minutes. The temperature quenched sample was characterized by in-situ Raman spectroscopy at 300 K. The Raman spectra at various regions of the laser heated sample at 9.3 GPa and at 300 K shows in addition to the characteristic Ge TO(Gamma) and C phonon mode, both of which are considerably softened, a new mode appearing at 203.3 cm(-1). We ascribe these to Ge-C bond formation.