Influence of arsenic species and growth temperature on the properties of GaAs/(Al,Ga)As superlattices grown by molecular beam epitaxy

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Abstract
The interrelation between dimeric and tetrameric arsenic sources and high‐ (700 °C) and low‐ (600 °C) growth temperatures on the properties of GaAs/(Al,Ga)As superlattices has been investigated. Superlattices consisting of alternating 100‐Å‐thick layers of GaAs and (Al,Ga)As were grown by molecular beam epitaxy and characterized by low temperature photoluminescence and excitation spectra. At low growth temperatures, the quality of the superlattice can be improved substantially by using As2 instead of As4. At 700 °C the arsenic species do not have as much an effect on the overall quality, but varying the group V/III ratio changes the relative intensities of the observed multiple excitonic peaks. These peaks are separated from one another by less than 1 meV, indicating extremely sharp and high quality interfaces and making it possible for the first time to relate them to excitonic processes.