1ST-ORDER RAMAN-SCATTERING IN HOMOEPITAXIAL CHEMICAL VAPOR-DEPOSITED DIAMOND AT ELEVATED-TEMPERATURES

The polarization discriminated first-order Raman spectrum in homoepitaxial chemical vapor deposited diamond was measured for the temperature range 300-1200 K. The dependences of Raman shift and width on temperature for natural type IIa diamond over the temperature range 300-2000 K are also given for comparison. Both the Stokes and anti-Stokes components were analyzed for their intensity, Raman shift, and width variation with temperature. The polarization of the Raman signal from the synthetic-diamond natural-diamond laminate at elevated temperatures was found to be the same as that at room temperature. The observed Raman shift, however, indicated the presence of internal stress. We attribute this homogeneous stress to a lattice mismatch which we speculate arises from hydrogen incorporation during growth. Following extended exposure to high temperatures in vacuo, the position of the first-order Raman peak at room temperature was found to relax to that measured for natural diamond.