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We have followed the evolution of the electrical and infrared absorption properties of two phosphorus‐doped epitaxial layers under a series of isochronal annealings between 800 °C and 1400 °C. In the as‐grown state, one sample is weakly compensated (Na/Nd= 0.15) while the other one is highly compensated (Na/Nd = 0.73). Under thermal annealing, both the electrical and infrared properties of the weakly compensated remain unchanged. On the contrary, the highly compensated sample becomes weakly compensated (Na/Nd = 0.15) after annealing at 1000 °C, 30 min while the neutral phosphorus concentration remains constant. This result is explained in terms of a migration of negatively charged acceptors followed by trapping on P+ donors. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The emission of secondary electrons from any material is governed by electron excitation in the bulk, their transport to the surface, and their escape through the surface into the vacuum. Here, we address the question of the transport of electrons in polycrystalline diamond and amorphous carbon membranes and discuss the factors that limit it. The results of the measurements of the escape depth of the secondary electrons from the membranes of submicron polycrystalline diamond and amorphous carbon films induced by the hydrogen ion impact are reported here. It is found that the escape depth for the secondary electrons emitted from diamond scales with the grain size of the crystallites in the polycrystalline diamond films and it can be very large. In contrast, for the case of the amorphous carbon membranes, we find this depth to be much shorter. The extremely high electron emission yield, which have been measured following the slowing down of the electrons or ions in diamond, can be explained by the fact that secondary electrons can move rather freely in diamond, hence, can reach the surface from large distances inside the diamond sample.