WAVELENGTH CONTROL AND RESIDUAL OXYGEN IN ALGAAS/INGAAS STRAINED QUANTUM-WELL HETEROSTRUCTURES GROWN BY MOLECULAR-BEAM EPITAXY

We have studied the residual oxygen in A]GaAs/GaAs/InGaAs heterostructures, and the effects of AS2 and As4 species and growth temperature (T(S)) 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 T(S) from 570 to 630-degrees-C or by postgrowth thermal annealing. Because of the very strong dependence of In sticking coefficient on T(S), the T(S) needs to be precisely controlled to obtain the desired emission wavelength. A solubility limit of approximately 8 X 10(17) CM-3 for Be is measured in AlAS at 700-degrees-C growth temperature. The residual oxygen level in undoped and Be-doped AlxGa1-xAs with x = 0. 3 5 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 0 level is the lowest with no variation with x.