Interplay between emission wavelength and s-p splitting in MOCVD-grown InGaAs/GaAs quantum dots emitting above 1.3 μ m

Abstract

The electronic structure of strain-engineered In0.75Ga0.25As/GaAs quantum dots emitting in the telecommunication O band is probed experimentally by photoluminescence excitation spectroscopy on the single-dot level. The observed resonances are attributed to p-shell states of individual quantum dots. The determined energy difference between s-and p-shells shows an inverse dependence on the emission energy. This observation is attributed to the varying indium content within individual quantum dots, indicating a way to control the quantum dot electronic structure. The impact of the size and indium content in the investigated quantum dots is simulated with an 8-band k·p model supporting the interpretation of the experimental data. † Present address:

Thermal stability of emission from single InGaAs/GaAs quantum dots at the telecom O-band

“…Noteworthy, the QDs analyzed here have even higher emission energies than those studied previously in Ref. 38 . Additionally, 8-band k .…”

“…2 c), we compare our findings with recently reported results of 8-band k . p calculations for such dots which yielded the s–p splitting of (60–80) meV 38 . Here, the lower splitting corresponds to the higher QD emission energy.…”

“…36: In our case the emission is dominated by positively charged complexes due to unintentional carbon p-doping in the metalorganic chemical vapour deposition (MOCVD) process 37 in contrast to negative trions exploited in the case of previous study. Additionally, differences between the two groups of nanostructures in QD morphology resulting from details of the growth procedure (i. e., exact growth parameters) are reflected in a modified electronic level structure and s–p energy splitting 38 . Moreover, in the present work the QDs are embedded in deterministically fabricated mesas which makes them relevant for high-yield single-photon sources and is crucial in view of their practical applications.…”

Atypical dependence of excited exciton energy levels and electron-hole correlation on emission energy in pyramidal InP-based quantum dots

“…Effective height for InAs/GaAs QDs from Ref. 27 as a function of average In content calculated according to Eq. ( 10 ).…”

“…Very recently, microphotoluminescence excitation 25 studies of such InAs/InP QDs showed that they possibly have a peculiar feature, namely, that the s – p -shell splitting for excitons in such systems may follow dependence on emission energy, which is opposite to the standard increasing one 26 . There was a single report on similar behavior of InAs/GaAs QDs with a strain-reducing layer, which was attributed to a strong variation of average In content within QD ensemble with a specific form of composition gradient within a QD 27 . Determination of such an atypical trend is practically essential, as it has to be taken into account when studies exploiting exciton excited states are performed.…”