Auger electron emission initiated by the creation of valence-band holes in graphene by positron annihilation

作者：Chirayath V A^*; Callewaert V; Fairchild A J; Chrysler M D; Gladen R W; Mcdonald A D; Imam S K; Shastry K; Koymen A R; Saniz R; Barbiellini B; Rajeshwar K; Partoens B; Weiss A H

来源：Nature Communications, 2017, 8(1): 16116.

DOI：10.1038/ncomms16116

Auger processes involving the filling of holes in the valence band are thought to make important contributions to the low-energy photoelectron and secondary electron spectrum from many solids. However, measurements of the energy spectrum and the efficiency with which electrons are emitted in this process remain elusive due to a large unrelated background resulting from primary beam-induced secondary electrons. Here, we report the direct measurement of the energy spectra of electrons emitted from single layer graphene as a result of the decay of deep holes in the valence band. These measurements were made possible by eliminating competing backgrounds by employing low-energy positrons (<1.25 eV) to create valence-band holes by annihilation. Our experimental results, supported by theoretical calculations, indicate that between 80 and 100% of the deep valence-band holes in graphene are filled via an Auger transition.

• 出版日期2017-7-13
• 单位东北大学