Growth of ZnO quantum dots on Si nano ripples

摘要

Substrates with nano-scale ripples are excellent templates for the deposition of semiconductor nanostructures. We have prepared quasi periodical nano-scale ripples on Si (100) substrates with spatial wavelength λ from - 70 to -150 nm by ion beam sputtering. ZnO QDs with diameters from 17 to -30 nm and heights from 2 to -4 nm have been successfully deposited by reactive ion beam sputter deposition. The QD size and distribution were found to be dependent both on growth conditions and spatial wavelength of the nano-scale ripple. On substrates with λ -150 nm, ZnO QDs were distributed evenly across the wafer, while on substrates with λ - 70 nm, ZnO QDs were preferentially located along the crest of the nano-scale ripples. As the QD height decreases from -4 to 2 nm, room temperature photoluminescence UV emission energy blue shifts by 80 meV. Possible sources of the blue shift are presented.