Temperature dependence of the photoluminescence from InP/GaAs type-II ultrathin quantum wells

Abstract

Temperature dependence of the photoluminescence (PL) spectra has been investigated for InP/GaAs type-II ultrathin quantum wells (QWs). Room temperature PL has been observed for 1.43 monolayer thick ultrathin QW. Fitting parameters of the Bose–Einstein empirical relation for ultrathin QWs show that the temperature dependence of PL peak energy is similar to the temperature dependence of the band gap for InP and GaAs materials. In addition, we have also determined the PL quenching mechanism from the Arrhenius-like plot of integrated PL intensity. Thermal escape of carriers from these ultrathin QWs into the GaAs barrier is mainly responsible for the PL quenching with temperature. This is also supported by the observation that the PL intensity related to the GaAs barrier increases with increasing temperature.

Structural and optical characterization of Mg-doped GaAs nanowires grown on GaAs and Si substrates

“…72 Concerning the evolution of the band gap energy of the WZ phase, Ahtapodov et al 28 showed for WZ GaAs nanowires a close behavior to the one of E ZB g for approximately the same temperature range studied in this work. Either the case, the experimental behavior is consistent with the observations of Singh et al 73 in which the temperature dependence of the peak energy of type II transitions follows the band gap variation of the quantum well and/or barrier materials. The blue shift of B 2 may be ascribed to the absence of a component in the high energy queue of the spectra.…”

“…11 and as observed experimentally for type II transitions in InP/GaAs ultrathin quantum wells. 73 Indeed, we observed a slight red shift of the emission for the growth on Si(111)substrate, as well as an increase of the relative intensity of the radiative transitions that are modeled by B 1 (at lower spectroscopic energies). These results support that the ZB segments in sample B are thicker and are present at a higher linear density.…”

New insights into the temperature-dependent photoluminescence of Mg-doped GaAs nanowires and epilayers

“…Nevertheless, the involvement of Mg acceptors cannot be ruled out, mainly in the large wurtzite segments given that: (i) the hole can be bound in a Mg acceptor state and recombine radiatively with the electron (in a ZB segment) via an indirect transition; (ii) spatially direct transitions can occur in WZ segments, though its recombination probability should be much lower than radiative transitions occurring at the WZ/ZB boundaries. 21,53 This discussion strengthens the necessity of having single-phase nanowires for a fundamental investigation of the doping issue and ultimately for their technological integration. The occurrence of a staggered band alignment at the WZ/ZB boundaries, which is inherent to indirect transitions, represents a potential obstacle for charge collection along the nanowire axis.…”

Surface photovoltage spectroscopy of an epitaxial ZnO/GaP heterojunction

“…It is noted that the values are similar within the error bar. The temperature dependence of the band gap provides important information about theexciton-phonon coupling strength [10,31,33,34]. Hence, to determine theexciton-phonon coupling strength, SPS measurements are performed at 15 different temperatures in the range10-300 K forZnO layers deposited at 500 °C and 300 °C, which have the best and worst crystalline qualities, respectively,among the studied samples.…”