Phosphorescence in high-pressure synthetic diamond

Abstract

Abstract Long-lived phosphorescence has been investigated in high-pressure synthetic boron-doped diamond. The spectrum exhibits two broad bands at peak energies of 2.1 and 2.5 eV after ultra-violet light excitation. The typical lifetime for both the bands shows a monotonous decrease from 50 s to 300 ms as the temperature rises from 200 to 400 K. The integrated intensities of the 2.1 and 2.5 eV bands increase as the temperature rises to 350 and 360 K, respectively. Beyond these temperatures, the intensities decrease rapidly as temperature rises. A model based on a recombination process involving both a shallow acceptor and a deep donor has been examined by theoretical fitting with the temperature dependence of the lifetime and the integrated intensity. It is concluded from the analysis that a shallow acceptor with an activation energy of 0.35 eV, which can be assigned as that of boron, plays a key role in the phosphorescence.