High optical quality of strained (111)B In0.12Ga0.88As/GaAs and In0.12Ga0.88As/Al0.2Ga0.8As multiple quantum wells

Abstract

We have investigated the growth of high quality In0.12Ga0.88As/GaAs and In0.12Ga0.88As/Al0.25Ga0.75As multiple quantum wells (MQWs) on 1 degrees misoriented (111)B and (100)GaAs substrates. Very narrow photoluminescence (PL) linewidths of 6.6 and 5.6 meV were measured in (100) and (111)B In0.12Ga0.88As/GaAs MQWs, respectively, which indicates the good optical quality of materials. In addition, more than an order of magnitude enhancement of PL intensity was measured from the (111)B sample relative to that from (100), which is consistent with the previously reported strongly enhanced optical property in (111)B AlGaAs/GaAs QW to (100). In contrast, under our normal growth conditions, narrow PL linewidth and large PL intensity were difficult to achieve in (111)B In0.12Ga0.88As/Al0.25Ga0.75As MQWs. Two-step growth with a high AlGaAs growth temperature was used to improve the optical quality of (111)B In0.12Ga0.88As/Al0.25Ga0.75As MQWs. A narrow PL linewidth of 5.1 meV and four times enhanced PL intensity can be obtained by such two-step growth. Cross-sectional transmission electron microscopy indicates defects generated in the 550 degrees C grown (111)B In0.12Ga0.88As/Al0.25Ga0.75As MQWs, while such defects were reduced or disappeared at a high AlGaAs growth temperature of 620 degrees C. (C) 1996 American Institute of Physics.