Magneto-optical studies of the correlation between interface microroughness parameters and the photoluminescence line shape in GaAs/Ga0.7Al0.3As quantum wells

In this work we analyze the relation between the interface microroughness and the full width at half maximum (FWHM) of the photoluminescence (PL) spectra for a GaAs/Ga0.7Al0.3As multiple quantum well (QW) system. We show that, in spite of the complex correlation between the microscopic interface-defects parameters and the QW optical properties, the Singh and Bajaj model [Appl. Phys. Lett. 44, 805 (1984)] provides a good quantitative description of the excitonic PL-FWHM. [S0163-1829(99)01424-1].6031519152

Influence of the temperature on the carrier capture into self-assembled InAs/GaAs quantum dots

Photoluminescence (PL) spectroscopy and atomic-force microscopy (AFM) were used to investigate the size evolution of InAs quantum dots on GaAs(001) as a function of the amount of InAs material. Different families of islands were observed in the AFM images and unambiguously identified in the PL spectra, together with the signal of the wetting layer. PL measurements carried out at low and intermediate temperatures showed a thermal carrier redistribution among dots belonging to different families. The physical origin of this behavior is explained in terms of the different temperature dependence of the carrier-capture rate into the quantum dots. At high temperatures, an enhancement of the total PL-integrated intensity of the largest-sized quantum dots was attributed to the increase of diffusivity of the photogenerated carriers inside the wetting layer. (C) 2003 American Institute of Physics.931016279628

Influence of illumination on the quantum mobility of a two-dimensional electron gas in Si delta-doped GaAs/In0.15Ga0.85As quantum wells

A series of GaAs/InGaAs quantum wells with a silicon delta-doped layer in the top barrier was investigated by Shubnikov-de Haas measurements as a function of the illumination time of the samples. During the illumination process strong modifications of the electronic density and the quantum mobility of each occupied subband were observed. Based on self-consistent calculations, the dominant mechanism which caused the changes in the subband quantum mobilities with illumination was elucidated.15212113

Illumination as a tool to investigate the quantum mobility of the two-dimensional electron gas in a Si delta-doped GaAs/In0.15Ga0.85As/GaAs quantum well

A systematic investigation of the transport properties of a GaAs/InGaAs quantum well electronically coupled to a silicon delta-doped layer was carried out as a function of the illumination time of the sample. Shubnikov-de Haas measurements allowed the determination of the quantum mobility of each occupied subband that could be accurately analyzed from the dark condition up to the continuous-illumination regime. The origin of the persistent-photoconductivity effect observed in the sample could be unambiguously determined and was confirmed by self-consistent calculations.65