A comparison study was carried out on the influence of the growth chemistry on the properties of AlxGa1-xAs and GaAs layers and quantum well structures. Triethylgallium, triethylaluminum, trimethylgallium, and trimethylaluminum were used in a various combinations during MOVPE growth of AlxGa1-xAs. Substantial reductions in the carbon incorporation can be achieved using the ethyl based growth chemistry. The observed change in the carbon incorporation with growth chemistry indicates a change in the decomposition kinetics and mechanisms between the various growth precursors. While triethylgallium can be directly substituted for trimethylgallium in the growth of AlxGa1-xAs, the use of triethyl aluminum requires particular care. Narrow quantum well structures were demonstrated using both ethyl and methyl based precursors. © 1986.