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Electronic Properties of Wide Bandgap Materials
Published online by Cambridge University Press: 10 February 2011
Abstract
Secondary electron emission spectroscopy is used to investigate the generation and transport of impact-ionized electrons in wide bandgap material. Secondary electron yield and energy distribution measurements from C(100) and CVD diamond samples are analyzed to obtain information about the internal gain and electron energy distribution following impact ionization, as well as the effects of the transport process on the internal electron distribution. By studying the emission from surfaces having a negative electron affinity (NEA), the total transmitted intensity and the full energy spectrum of the internal electrons are revealed in the measurements. Energy spectra measured from the diamond samples contain a low-energy peak whose energy position and width are independent of incident beam energy. This suggests that the peak represents the electron distribution produced by impact-ionization events. A large percentage of the total emitted electrons lie within this peak, indicating that the impact-ionization process is very efficient at generating low-energy electrons. Very high yields are measured from both samples, establishing the presence of high internal gain and efficient electron transport in the material. From the linear slope of the yield curves, the escape depth of the low-energy electrons is deduced to be much larger than ˜ 0.1 μm in both diamond samples.
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- Copyright © Materials Research Society 1998
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