CALORIMETRIC ABSORPTION-SPECTROSCOPY AND PHOTOLUMINESCENCE STUDY OF DEFECTS IN DIAMOND

Defects in diamond, both plasma-assisted chemical vapor deposition grown polycrystalline and electron-irradiated type IIa natural diamond, were studied using calorimetric absorption spectroscopy and photoluminescence. Calorimetric absorption spectroscopy is a highly sensitive low temperature technique which measures the non-radiative recombination component of a given optical absorption. For the first time calorimetric absorption spectroscopy has been used to investigate a wide band gap crystalline material, namely diamond. The radiative efficiency of the 1.68 and 1.639 eV absorption in plasma assisted chemical vapor deposition diamond grown on silicon and the 1.673 eV absorption in electron irradiated natural diamond have been studied using a combination of calorimetric absorption spectroscopy and photoluminescence measurements. The radiative efficiency of the 1.68 eV absorption is found to be much greater than that of the 1.639 eV absorption. Also, the 1.673 eV neutral vacancy absorption in irradiated bulk diamond is seen to have a highly non-radiative recombination character.