Fine structure in the secondary electron emission peak for diamond crystalwith (100) negative electron affinity surface

A fine structure was discovered in the low-energy peak of the secondary ele ctron emission spectra of the diamond surface with negative electron affini ty. We studied this structure for the (100) surface of the natural type-IIb diamond crystal. We have found that the low-energy peak consists of a tota l of four maxima, The relative energy positions of three of them could be r elated to the electron energy minima near the bottom of the conduction band . The fourth peak, having the lowest energy, was attributed to the breakup of the bulk exciton at the surface during the process of secondary electron emission. (C) 1998 American Insitute of Physics. [S0003-6951(98)02751-X].