Direct demonstration of a misfit strain-generated electric field in a [111] growth axis zinc-blende heterostructure

Abstract

We report the first direct demonstration of a strain-generated built-in electric field in a (111) oriented strained-layer heterostructure. We present a model which describes the accommodation of the misfit strain in a lattice-mismatched quantum well, and the resulting generation of a longitudinal electric field via the piezoelectric effect. On a (111)B GaAs substrate, we grew the quantum well in the intrinsic region of a p-i-n diode such that the strain-generated electric field in the quantum well opposes the weaker built-in electric field of the diode. Under reverse bias operation, photoconductivity measurements show a quadratic blue shift of the quantum well electroabsorption peaks, in contrast to the red shifts normally observed in the quantum-confined Stark effect. The measured blue shifts demonstrate an electric field strength of 1.7×105 V/cm, which agrees with theory to within the accuracy of the measured sample characteristics.