Effect of doping on the photoluminescence of multilayer Ge quantum dots deposited on Si(001) substrate

Abstract

Four-bilayer Ge quantum dots (QDs) with Si spacers were epitaxially grown on Si(001) substrates by means of ultrahigh vacuum chemical vapor deposition. In two samples, Ge QDs were in situ doped with phosphorus or boron, separately. Surface morphology and room temperature photoluminescence (PL) of multilayer Ge/Si QDs wer studied. Compared with the undoped Ge QDs, phosphorus-doping did not change the morphology of Ge QDs, enhanced PL wer observed from the phosphorus-doped Ge QDs. But reduction of Ge QDs density and PL intensity wer observed from the boron-doped Ge QDs. The intensity enhancement of PL could be attributed to the sufficient supply of electrons in Ge QDs for radiative recombination.