Epitaxy of LiF on Ge(100)

It is shown that LiF(100) films with the electronic properties of cleaved bulk LiF crystals can be grown epitaxially on Ge(100). These include an exceptionally large, negative electron affinity of -2.7 eV, which leads to intense photoemission at zero kinetic energy. The valence band offset ranges from 7.3-7.6 eV.