Optical characterization of In-flushed InAs/GaAs quantum dots emitting a broadband spectrum with multiple peaks at ~1 μm

Abstract

We investigated optical properties of In-flushed InAs quantum dots (QDs) grown on a GaAs substrate by molecular beam epitaxy. By using the In-flush technique for setting the height of self-assembled InAs QDs, we have tuned the emission wavelength of InAs QDs to the ~1 μm regime, which can be utilized as a non-invasive and deeply penetrative probe for biological and medical imaging systems. The controlled emission exhibited a broadband spectrum comprising multiple peaks with an interval of approximately 30 meV. We examined the origin of the multiple peaks using spectral and time-resolved photoluminescence, and concluded that it is attributed to monolayer step fluctuations in the height of the In-flushed QDs. This feature can be advantageous for realizing a broadband light source centered at the ~1 μm regime, which is especially suitable for the non-invasive cross-sectional biological and medical imaging system known as optical coherence tomography.

1.5 μm quantum-dot diode lasers directly grown on CMOS-standard (001) silicon

“…Moreover, additional tuning of the QDs growth parameters led to an over 4 times stronger peak PL intensity and 1.6 times narrower FWHM than the previous batch of QDs 21 . Here, the multi-modal size distribution is attributed to the non-uniformity of QD sizes 24,25 , rather than the effects of the stacking process, as evidenced by the multi-peak PL spectrum of single layer QDs in Fig. 2(a).…”

Investigations on morphology, growth mode and indium incorporation in MOCVD grown InGaN/n-GaN heterostructures

“…XPS was used to estimate the composition of the grown InGaN layers. accounts for the Boltzmann distribution function in InGaN nanoislands [31]. Also, it is noted that the high intensity emission peaks at 539 nm, 549 nm and 543 nm appear with varying TMIn flow of InGaN nanoisland structures.…”