Effect of the growth parameters on the luminescence properties of high-quality GaAs/AlGaAs multiquantum wells on (111)A substrates by metal organic vapor phase epitaxy

We report on a study of the growth parameters and their effect on the struc tural and optical properties of GaAs/AlGaAs multiquantum well (MQW) structu res grown on novel (111)A-oriented GaAs substrates by atmospheric-pressure metalorganic vapor-phase epitaxy. The MQW structures have 25 periods with w ell widths ranging from 75 to 45 Angstrom and an Al fraction in the barrier s of around 25% and were grown at 600 degrees C using V/III ratios ranging from 52 to 261 and various growth rates on exact and misoriented(1 1 1)A su bstrates. High-resolution X-ray diffractometry was used to assess the cryst al quality and obtain structural information. The growth rates for GaAs on (1 1 1)A and (1 0 0) oriented substrates are compared. The optical quality was evaluated by low-temperature photoluminescence (PL) spectroscopy. We de termined the optimum growth conditions to obtain high structural quality an d PL emission intensity. A PL line width of 10.5 meV was achieved, which is the lowest value reported to date for GaAs/AlGaAs MQWs on (1 1 1)A or (1 1 1)B GaAs by any growth technique, corresponding to less than a +/- 1 monol ayer fluctuation of the well width over the 25 periods. (C) 1998 Elsevier S cience B.V. All rights reserved.