Imaging of charge transport properties in polycrystalline CVD diamond using IBIC and IBIL microscopy

Ion beam induced charge (IBIC) and ion beam induced luminescence (IBIL) results of polycrystalline CVD diamond radiation detectors are presented. These detectors were designed as alpha particle and UV sensors, and were constructed with a coplanar electrode structure, fabricated only on the growth side of the diamond film. IBIC results show the different efficiencies of individual 10–20 μm wide grains at facilitating charge transport at different locations away from the surface metallisation. IBIL results show that some of the large grains which exhibit poor charge collection give a high luminescence yield, whereas other regions exhibit both a low IBIC and IBIL signals. These results directly show that the charge collection efficiency in the inter-electrode region is limited both by the size of the diamond crystallites and also by the high luminescence yield of certain grains.