Emission wavelength variation of InAs quantum dots grown on GaAs using As<inf>2</inf> molecules in molecular beam epitaxy

Abstract

InAs quantum dots (QDs) were grown on GaAs by molecular beam epitaxy using As 2 molecules (As 2 -QDs) and were structurally and optically characterized. Photoluminescence (PL) measurements revealed unique optical properties of the As 2 -QDs, which differ from InAs QDs grown with As 4 (As 4 -QDs). As 2 -QDs exhibited PL emission centered at 1.14–1.21 µm, which is shorter than that of As 4 -QDs (1.21–1.22 µm). In addition, the emission peak wavelength was continuously redshifted with a growth interruption time (Δt), which is an interval between the growth of the As 2 -QDs and capping of the QDs with a GaAs layer. Considering that no apparent difference of structural property was observed among as-grown As 2 -QDs and As 4 -QDs with various Δt, the peak shift can be attributed to the deformation of QDs during the capping process. The continuous peak shift can be applied to control the emission wavelength of InAs QDs, and this enables a broadband light source by combining the As 2 -QDs with different peak wavelengths.