Direct measurement of piezoelectric field in a lsqb;111rsqb;B grown InGaAs/GaAs heterostructure by Franzndash;Keldysh oscillations

摘要

We report the first photoreflectance measurement of strainhyphen;induced piezoelectric field in a (111)B InGaAs/GaAs structure. The InGaAs quantum well was pseudomorphically grown in the undoped regions of a GaAs undopedndash;heavily doped structure. Four structures, two each with the same layer structures but different orientation, (111)B and (100), were used in this study. The electric fields in the undoped GaAs region were measured by Franzhyphen;Keldysh oscillations in photoreflectance. All the samples have a surface barrier height of about 0.7 eV. However, the measured electric field is 30percnt; stronger in the (111)B sample compared to the (100) sample. We attribute this difference to the strainhyphen;induced electric field in the (111)B sample. The piezoelectric field in (111)B strained In0.15Ga0.85As obtained in this measurement is 2.2plusmn;0.5times;105V/cm, which agrees very well with theory.