Quantum confinement observed in Ge nanodots on an oxidized Si surface

Quantum-confinement effect in the valence band of germanium nanodots is clearly measured by means of photoemission spectroscopy. The spherical dots of 3--100.3em0exnm in diameter were prepared on a 0.3-nm-thick SiO₂ film on Si(111) substrate. Dot-size dependence of the band edge matched the ones expected from the spherical quantum dot model and calculated from the semiempirical simulation recently reported.