Photoluminescence from strained GaAs/In 0.12Ga 0.88As multiple quantum-wells grown with and without growth interruption by molecular beam epitaxy

Abstract

Low-temperature photoluminescence measurements were carried out to assess the changes in the properties of strained GaAs/InGaAs/GaAs multi-quantum-wells grown by molecular beam epitaxy at different substrate (well) temperatures with and without growth interruption at the heterointerfaces. Sharp exciton peaks were observed in the spectra, some with linewidths as low as 1.2 meV. The spectra from samples grown with interruption were narrower than those without, indicating structural modifications and improvements at the interfaces. The linewidths were narrower in samples grown with the bottom InGaAs/GaAs interface interrupted or by increasing the duration of the interrupt time. The narrowest linewidths were seen in samples with both the top GaAs/InGaAS and bottom InGaAs/GaAs interfaces interrupted. A consistent reduction in the linewidth was observed in wells grown at higher temperatures, most likely due to greater indium reevaporation leading to a reduction in strain, well-width and interface fluctuations.