THE EFFECT OF GROWTH INTERRUPTION ON THE PHOTOLUMINESCENCE LINEWIDTH OF GAAS/INGAAS QUANTUM-WELLS GROWN BY MOLECULAR-BEAM EPITAXY

Low-temperature photoluminescence measurements were carried out to assess the interfacial properties of strained GaAs/InGaAs quantum wells grown by molecular beam epitaxy at different well temperatures with and without growth interruption at the heterointerfaces. Sharp exiton peaks were observed in the spectra, some with linewidths as low as 1.2 meV. The spectra from samples with growth interruption at the interface were narrower, indicating structural improvements at the interfaces. The linewidths were narrower in samples with growth interruption at the bottom InGaAs/GaAs interface or by increasing the duration of the interrupt time. The narrowest linewidths were seen in samples with growth at both the top GaAs/InGaAs and bottom InGaAs/GaAs interfaces interrupted. A 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.