Free carrier effects on the optical properties of InGaAsInP quantum wells

Abstract In this paper we present photoluminescence (PL) and photoluminescence excitation (PLE) spectra as a function of electron sheet carrier density (n s ) in a Schottky gated 110 A wide InGaAsInP quantum well. Major free carrier effects are observed on both the PL and PLE spectra. The PL spectra show a high energy cut-off at the electron Fermi energy for n s = 1.4 × 10 11 cm −2 . As n s tends to zero the PL linewidth decreases from the high energy side, as expected for free carrier broadening. At the same time the n=1 transitions observed in PLE show a marked increase in oscillator strength and narrowing as n s tends to zero. The PLE results are discussed in terms of phase space filling and the variation of many body effects as a function of n s . The many body nature of the PLE transitions at the Fermi energy, for finite n s , is further demonstrated by the anomalous temperature dependence of the n=1 heavy hole transition.