Temperature dependence of the lowest excitonic transition for an InAs ultrathin quantum well

Abstract

Temperature dependent photoluminescence and photoreflectance techniques are used to investigate the lowest excitonic transition of InAs ultrathin quantum well. It is shown that the temperature dependence of the lowest energy transition follows the band gap variation of GaAs barrier, which is well reproduced by calculated results based on the envelope function approximation with significant corrections due to strain and temperature dependences of the confinement potential. A redshift in photoluminescence peak energy compared to photoreflectance is observed at low temperatures. This is interpreted to show that the photoluminescence signal originates from the recombination of carriers occupying the band-tail states below the lowest critical point.

An accurate determination of the electronic transitions of InAs/InGaAs/InP quantum dots for midinfrared lasers using simultaneous complementary spectroscopic techniques

“…In such cases, SPS becomes a potentially useful tool since it can measure essentially very small values of the absorption coefficient such as in the case of InAs QDs [19][20][21][22] or even ultrathin InAs QWs. 23 This was the main reason we also applied the complementary SPS technique to the InAs/InGaAs/InP QD sample and indeed found a measurable signal at all temperatures. Figure 6 shows representative SPS spectra at three selected temperatures, showing that the overall magnitude of the SPS signal first increases between ϳ9 and ϳ100 K but then subsequently drops.…”

Spectroscopic investigations of MOVPE-grown InGaAs/GaAs quantum wells with low and high built-in strain

“…6 where we present the SPS spectrum for an InAs ultrathin QW. Thickness of this QW is kept very low (3.6 Å ) such that no relaxation is seen in HRXRD measurement and an estimate of QW thickness can easily be obtained from the simulation of HRXRD data [8]. We did not observe any PL signal above 120 K for this sample.…”

“…Therefore, it is confirmed that the transition seen at 1.36 eV is related to the InAs/GaAs ultrathin QW only. From quantum mechanical calculations [8], we identify this as e 1 -hh 1 transition. Features A, Q and B are reported earlier and are related to semi-insulating GaAs substrates [6,9].…”

Structural, Optical And Electrical Properties Of MOVPE Grown InP∕GaAs Type-II Ultrathin Quantum Well

“…7 Ultrathin quantum wells (QWs) with typical thickness of 1-2 monolayer (ML) have been also studied due to their unique electronic and optical properties leading to their use in the optoelectronic devices. 8,9 The issue of type-II band alignment for InP/GaAs heterostructure has been addressed by several groups, where it is understood that the electrons (holes) are confined in the conduction (valance) band of InP (GaAs) respectively. 1,7,10-12 There exist several reports dealing with the optical properties of InP/GaAs type-II quantum dots (QDs), where signature of InP/GaAs ultrathin QW, known as wetting layer in the QD structures, has been observed in the low temperature photoluminescence (PL) spectra.…”