We have studied the residual oxygen in AlGaAs/GaAs/InGaAs heterostructures, and the effects of As2 and As4 species and growth temperature (TS) on optical properties of InGaAs quantum wells (QW) for AlGaAs/InGaAs strained QW lasers. In clean growth conditions, the optical properties of InGaAs QWs are insensitive to the As beam used, and the luminescence intensity does not increase with increasing TS from 570 to 630 °C or by postgrowth thermal annealing. Because of the very strong dependence of In sticking coefficient on TS, the TS needs to be precisely controlled to obtain the desired emission wavelength. A solubility limit of ∼8×1017 cm−3 for Be is measured in AlAS at 700 °C growth temperature. The residual oxygen level in undoped and Be-doped AlxGa1−xAs with x=0.35 was found to be higher by a factor 2 than in x=0.5, 0.6, and 1.0 compositions. In Si-doped AlxGa1−xAs, the O level is the lowest with no variation with x.