Novel approach to enhance the optical property in AlGaAs and InGaAlP by natural ordering during growth

Long range alloy ordering is observed by cross-sectional TEM in both (111)A and (111)B AlGaAs. We have measured a 31 meV photoluminescence (PL) peak energy red shift of (111)A and (111)B Al_0.30Ga_0.70As to that of (100), while the PL integrated intensity in (111)A and (111)B is near an order of magnitude larger than that of (100). The ordering effect is reduced at a high growth temperature of 700 °C and the best PL linewidth of 17 and 3 meV are obtained in (111)A Al_0.40Ga_0.60As and (111)B Al_0.30Ga_0.70As, respectively. In the In_0.6Ga_0.4P/InGaAlP MQW, similar ordering related PL peak energy red shift of 37 meV and ~2 times enhanced PL integrated intensity are observed for 0° sample to that of 15°.