Positron lifetime spectroscopy with optical excitation: a case study of natural diamond

In this paper, we report positron lifetime results obtained under high-power steady-state and transient optical excitation. We present a model for analysing the results. The method has been applied to vacancy clusters in natural diamond, for which we self-consistently analyse optoelectronic constants such as optical absorption cross-section and hole recombination cross-section. The temperature dependences of transient and steady-state measurements are studied, suggesting the possibility of analysing the positron trapping to extended defects and vacancy clusters in semiconductors. (paper)