Exciton resonances in ultrathin InAs/InP quantum wells

Abstract

We have performed detailed optical measurements of ultrathin InAs/InP quantum wells grown by metal organic vapor phase epitaxy. Photoluminescence excitation spectra reveal the excitonic resonances associated with two- and three-monolayer thick InAs layers while polarization-dependent measurements clearly show the heavy- or light-hole nature of the resonances. These resonances, together with their emission bands, can be detected on the same sample, indicating the presence of well defined regions of different InAs layer thickness. We find that the energy position of the excitonic resonances cannot be reproduced by effective mass calculations based on the envelope function approximation.

Excitons in ultrathin InAs/InP quantum wells: Interplay between extended and localized states

“…[3][4][5][6][7][8][9][10][11][12] However, the electronic states in ultrathin QWs are still not well understood. 3,6,10,11,15,16 The energy position of heavy-hole excitonic transitions deduced from the PL spectra can also be well reproduced by EFA. But EFA is highly questionable in the case of QWs which are only a few monolayers ͑ML͒ thick, 13 as indicated by recent tightbinding calculations on the InAs/GaAs system which depart significantly from the EFA approach.…”

Growth and characterization of InAs on (100) InP ultrathin single quantum wells using tertiarybutylarsine and tertiarybutylphosphine

“…This shape difference is very well reproduced by the simulated spectra based on the Takagi-Taupin equations of the dynamical diffraction theory. According to calculations based on the envelope function approximation, 6,16,17 these energies can be made to correspond to heavy hole and light hole to electron transitions in 2 and 3 ML InAs quantum wells, respectively, provided that a conduction band gap offset ⌬Ec of 75% is used and an energy offset of 40 meV is added to the calculated values. Since the lattice parameter along the growth axis of InAs strained in InP is 6.26 Å, these thicknesses correspond to 1.88Ϯ0.15 and 2.78Ϯ0.15 ML, respectively.…”

Carrier thermal escape in families of InAs/InP self-assembled quantum dots

“…The PLE spectra of peaks A1 and A2 are similar to what was previously reported in thin InAs QWs. 27,30 They show an edge at 1.19Ϯ 0.01 eV and a resonance at 1.31Ϯ 0.01 eV that correspond, respectively, to the electron to heavy-and light-hole transitions in a 2-ML-thick InAs/InP QW as calculated with the tight-binding method. 27,31 It follows that the high-energy tail of the emission from sample A at low temperature corresponds to residual emission from the WL.…”